#include <bits/stdc++.h>

#define forn(i, n) for (int i = 0; i < int(n); i++)

using namespace std;


int main() {
	int tc;
	scanf("%d", &tc);
	while (tc--){
		int n;
		scanf("%d", &n);
		int p = 0, c = 0;
		bool fl = true;
		forn(i, n){
			int x, y;
			scanf("%d%d", &x, &y);
			if (x < p || y < c || y - c > x - p)
				fl = false;
			p = x, c = y;
		}
		puts(fl ? "YES" : "NO");
	}
	return 0;
}

fun main() {
    val T = readLine()!!.toInt()
    for (tc in 1..T) {
        val (n, x) = readLine()!!.split(' ').map { it.toInt() }
        val a = readLine()!!.split(' ').map { it.toInt() }.sortedDescending()

        var cnt = 0
        var sum = 0L
        while (cnt < n && sum + a[cnt] >= (cnt + 1) * x.toLong()) {
            sum += a[cnt]
            cnt++
        }
        println(cnt)
    }
}

#include <bits/stdc++.h>

using namespace std;

#define forn(i, n) for (int i = 0; i < int(n); ++i)

typedef long long li;

const int N = 300 * 1000 + 13;

int n;
li a[N], b[N];

void solve() {
	scanf("%d", &n);
	forn(i, n) scanf("%lld%lld", &a[i], &b[i]);
	
	li ans = 0, mn = 1e18;
	forn(i, n) {
		int ni = (i + 1) % n;
		li val = min(a[ni], b[i]);
		ans += a[ni] - val;
		mn = min(mn, val);
	}
	ans += mn;
	printf("%lld\n", ans);
}

int main() {
	int T;
	scanf("%d", &T);
	forn(i, T)
		solve();
}

#include<bits/stdc++.h>

using namespace std;

#define fore(i, l, r) for(int i = int(l); i < int(r); i++)
#define sz(a) int((a).size())

#define x first
#define y second

typedef long long li;
typedef long double ld;
typedef pair<int, int> pt;

int n;
li l, r;

inline bool read() {
	if(!(cin >> n >> l >> r))
		return false;
	return true;
}

bool intersect(li l1, li r1, li l2, li r2) {
	return min(r1, r2) > max(l1, l2);
}

vector<int> ans;

void calc(int lf, int rg, li &id) {
	if(lf == rg) return;
	
	if(intersect(l, r, id, id + 2 * (rg - lf))) {
		fore(to, lf + 1, rg + 1) {
			if(l <= id && id < r)
				ans.push_back(lf);
			id++;
			
			if(l <= id && id < r)
				ans.push_back(to);
			id++;
		}
	} else
		id += 2 * (rg - lf);
	
	calc(lf + 1, rg, id);
	
	if(lf == 0) {
		if(l <= id && id < r)
			ans.push_back(lf);
		id++;
	}
}

inline void solve() {
	ans.clear();
	li id = 0;
	l--;
	calc(0, n - 1, id);
	
	assert(sz(ans) == r - l);
	assert(id == n * li(n - 1) + 1);
	
	for(int v : ans)
		cout << v + 1 << " ";
	cout << endl;
}

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
	int tt = clock();
#endif
	ios_base::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	cout << fixed << setprecision(15);
	
	int tc; cin >> tc;
	
	while(tc--) {
		read();
		solve();
		
#ifdef _DEBUG
		cerr << "TIME = " << clock() - tt << endl;
		tt = clock();
#endif
	}
	return 0;
}

#include <bits/stdc++.h>

#define forn(i, n) for (int i = 0; i < int(n); i++)

using namespace std;

const int MOD = 998244353;

int add(int a, int b){
	a += b;
	if (a >= MOD)
		a -= MOD;
	if (a < 0)
		a += MOD;
	return a;
}

int mul(int a, int b){
	return a * 1ll * b % MOD;
}

int binpow(int a, int b){
	int res = 1;
	while (b){
		if (b & 1)
			res = mul(res, a);
		a = mul(a, a);
		b >>= 1;
	}
	return res;
}

int main() {
	long long d;
	scanf("%lld", &d);
	int q;
	scanf("%d", &q);
	
	vector<long long> primes;
	for (long long i = 2; i * i <= d; ++i) if (d % i == 0){
		primes.push_back(i);
		while (d % i == 0) d /= i;
	}
	if (d > 1){
		primes.push_back(d);
	}
	
	vector<int> fact(100), rfact(100);
	fact[0] = 1;
	for (int i = 1; i < 100; ++i)
		fact[i] = mul(fact[i - 1], i);
	rfact[99] = binpow(fact[99], MOD - 2);
	for (int i = 98; i >= 0; --i)
		rfact[i] = mul(rfact[i + 1], i + 1);
	
	forn(i, q){
		long long x, y;
		scanf("%lld%lld", &x, &y);
		vector<int> up, dw;
		for (auto p : primes){
			int cnt = 0;
			while (x % p == 0){
				--cnt;
				x /= p;
			}
			while (y % p == 0){
				++cnt;
				y /= p;
			}
			if (cnt < 0) dw.push_back(-cnt);
			else if (cnt > 0) up.push_back(cnt);
		}
		int ans = 1;
		ans = mul(ans, fact[accumulate(up.begin(), up.end(), 0)]);
		for (auto it : up) ans = mul(ans, rfact[it]);
		ans = mul(ans, fact[accumulate(dw.begin(), dw.end(), 0)]);
		for (auto it : dw) ans = mul(ans, rfact[it]);
		printf("%d\n", ans);
	}
	
	return 0;
}

#include<bits/stdc++.h>

using namespace std;

typedef long long li;
const li INF64 = li(1e18);
const int N = 500043;

li f[N];

li get(int x)
{
    li ans = 0;    
    for (; x >= 0; x = (x & (x + 1)) - 1)
        ans += f[x];
    return ans;
}

void inc(int x, li d)
{
    for (; x < N; x = (x | (x + 1)))
        f[x] += d;    
}

li get(int l, int r)
{
    return get(r) - get(l - 1);
}

li dp[N];
int a[N], b[N], p[N];
int n, m;

int main()
{
    scanf("%d", &n);
    for(int i = 0; i < n; i++)
        scanf("%d", &a[i]);
    for(int i = 0; i < n; i++)
        scanf("%d", &p[i]);
    scanf("%d", &m);
    for(int i = 0; i < m; i++)
        scanf("%d", &b[i]);

    for(int i = 0; i < n; i++)
        dp[i] = -INF64;
    map<int, vector<int> > pos;
    for(int i = 0; i < n; i++)
        pos[a[i]].push_back(i);
    set<pair<int, int> > q;
    for(int i = 0; i < n; i++)
        q.insert(make_pair(a[i], i));
    
    for(auto x : pos[b[0]])
        dp[x] = p[x];
    while(!q.empty() && q.begin()->first <= b[0])
    {
        int k = q.begin()->second;
        q.erase(q.begin());
        if(p[k] > 0)
            inc(k, p[k]);
    }  

    for(int i = 1; i < m; i++)
    {
        int i1 = b[i - 1], i2 = b[i];
        vector<int> both_pos;
        for(auto x : pos[i1])
            both_pos.push_back(x);
        for(auto x : pos[i2])
            both_pos.push_back(x);
        li best = -INF64;
        int last = -1;
        sort(both_pos.begin(), both_pos.end());
        for(auto x : both_pos)
        {
            best += get(last + 1, x);
            last = x;
            if(a[x] == i1)
                best = max(best, dp[x]);
            else
                dp[x] = best + p[x];
        }
        while(!q.empty() && q.begin()->first <= i2)
        {
            int k = q.begin()->second;
            q.erase(q.begin());
            if(p[k] > 0)
                inc(k, p[k]);
        }
    }

    li best_dp = -INF64;
    for(int i = 0; i < n; i++)
        if(a[i] == b[m - 1])
            best_dp = max(best_dp, dp[i] + get(i + 1, n - 1));
    li ans = 0;
    for(int i = 0; i < n; i++)
        ans += p[i];
    ans -= best_dp;
    if(ans > li(1e15))
        puts("NO");
    else     
        printf("YES\n%lld\n", ans);
    
}

#include<bits/stdc++.h>

using namespace std;

#define forn(i, n) for(int i = 0; i < n; i++)
#define sz(a) ((int)(a).size())

const int LOGN = 20;
const int N = (1 << LOGN);

typedef long double ld;
typedef long long li;

const ld PI = acos(-1.0);

struct comp 
{
    ld x, y;
    comp(ld x = .0, ld y = .0) : x(x), y(y) {}
    inline comp conj() { return comp(x, -y); }
};

inline comp operator +(const comp &a, const comp &b) 
{
    return comp(a.x + b.x, a.y + b.y);
}

inline comp operator -(const comp &a, const comp &b) 
{
    return comp(a.x - b.x, a.y - b.y);
}

inline comp operator *(const comp &a, const comp &b) 
{
    return comp(a.x * b.x - a.y * b.y, a.x * b.y + a.y * b.x);
}

inline comp operator /(const comp &a, const ld &b) 
{
    return comp(a.x / b, a.y / b);
}

vector<comp> w[LOGN];
vector<int> rv[LOGN];

void precalc() 
{
    for(int st = 0; st < LOGN; st++) 
    {
        w[st].assign(1 << st, comp());
        for(int k = 0; k < (1 << st); k++) 
        {
            double ang = PI / (1 << st) * k;
            w[st][k] = comp(cos(ang), sin(ang));
        }
        
        rv[st].assign(1 << st, 0);
        if(st == 0) 
        {
            rv[st][0] = 0;
            continue;
        }
        int h = (1 << (st - 1));
        for(int k = 0; k < (1 << st); k++)
            rv[st][k] = (rv[st - 1][k & (h - 1)] << 1) | (k >= h);
    }
}

inline void fft(comp a[N], int n, int ln, bool inv) 
{
    for(int i = 0; i < n; i++) 
    {
        int ni = rv[ln][i];
        if(i < ni)
            swap(a[i], a[ni]);
    }
    
    for(int st = 0; (1 << st) < n; st++) 
    {
        int len = (1 << st);
        for(int k = 0; k < n; k += (len << 1)) 
        {
            for(int pos = k; pos < k + len; pos++) 
            {
                comp l = a[pos];
                comp r = a[pos + len] * (inv ? w[st][pos - k].conj() : w[st][pos - k]);
                
                a[pos] = l + r;
                a[pos + len] = l - r;
            }
        }
    }
    
    if(inv) for(int i = 0; i < n; i++)
        a[i] = a[i] / n;
}

comp aa[N];
comp bb[N];
comp cc[N];

inline void multiply(comp a[N], int sza, comp b[N], int szb, comp c[N], int &szc) 
{
    int n = 1, ln = 0;
    while(n < (sza + szb))
        n <<= 1, ln++;
    for(int i = 0; i < n; i++)
        aa[i] = (i < sza ? a[i] : comp());
    for(int i = 0; i < n; i++)
        bb[i] = (i < szb ? b[i] : comp());
        
    fft(aa, n, ln, false);
    fft(bb, n, ln, false);
    
    for(int i = 0; i < n; i++)
        cc[i] = aa[i] * bb[i];
        
    fft(cc, n, ln, true);
    
    szc = n;
    for(int i = 0; i < n; i++)
        c[i] = cc[i];
}

comp a[N];
comp b[N];
comp c[N];

vector<int> p_function(const vector<int>& v)
{
    int n = v.size();
    vector<int> p(n);
    for(int i = 1; i < n; i++)
    {
        int j = p[i - 1];
        while(j > 0 && v[j] != v[i])
            j = p[j - 1];
        if(v[j] == v[i])
            j++;
        p[i] = j;   
    }
    return p;
}

int p[26];
char buf[N];
string s, t;

int main()
{
    precalc();                  
    for(int i = 0; i < 26; i++)
    {
        scanf("%d", &p[i]);
        p[i]--;
    }
    scanf("%s", buf);
    s = buf;
    scanf("%s", buf);
    t = buf;

    int n = s.size();
    int m = t.size();
    vector<int> color(26, 0);
    vector<vector<int> > cycles;
    for(int i = 0; i < 26; i++)
    {
        if(color[i])
            continue;
        vector<int> cycle;
        int cc = cycles.size() + 1;
        int cur = i;
        while(color[cur] == 0)
        {
            cycle.push_back(cur);
            color[cur] = cc;
            cur = p[cur];
        }
        cycles.push_back(cycle);
    }

    vector<int> ans(m - n + 1);
    vector<int> s1, t1;
    for(int i = 0; i < n; i++)
        s1.push_back(color[int(s[i] - 'a')]);
    for(int i = 0; i < m; i++)
        t1.push_back(color[int(t[i] - 'a')]);
    vector<int> st = s1;
    st.push_back(0);
    for(auto x : t1)
        st.push_back(x);
    vector<int> pf = p_function(st);
    for(int i = 0; i < m - n + 1; i++)
        if(pf[2 * n + i] == n)
            ans[i] = 1;
    map<char, comp> m1, m2;
    for(auto cur : cycles)
    {
        int k = cur.size();
        for(int i = 0; i < k; i++)
        {
            ld ang1 = 2 * PI * i / k;
            ld ang2 = (PI - 2 * PI * i) / k;
            m1[char('a' + cur[i])] = comp(cosl(ang1), sinl(ang1));
            m2[char('a' + cur[i])] = comp(cosl(ang2), sinl(ang2));
        }
    }

    ld ideal = 0;
    for(int i = 0; i < n; i++)
        ideal += (m1[s[i]] * m2[s[i]]).x;
    reverse(s.begin(), s.end());
    for(int i = 0; i < n; i++)                  
        a[i] = m1[s[i]];                
    for(int i = 0; i < m; i++)
        b[i] = m2[t[i]];
    int szc;
    multiply(a, n, b, m, c, szc);
    for(int i = 0; i < m - n + 1; i++)
        if(fabsl(c[i + n - 1].x - ideal) > 0.01)
            ans[i] = 0;
    

    for(int i = 0; i < m - n + 1; i++)
        printf("%d", ans[i]);
    return 0;
}