#include<bits/stdc++.h>
#define eb emplace_back
#define ll long long
#define w(t) while(t--)
#define F first
#define S second
#define pii pair<int,int>
#define pll pair<ll,ll>
using namespace std;
set<int> s[100010];
ll a[200010];
struct aaa{
	ll val;
	int idx;
}b[100010];
int main(){
	ios::sync_with_stdio(0);cin.tie(0);
	int n,m,l,c,d;
	cin>>n>>m>>l;
	ll ans=0;
	for(int i=0;i<n;i++) cin>>a[i];
	for(int i=0;i<m;i++){
		cin>>b[i].val;
		b[i].idx=i;
	}
	for(int i=0;i<l;i++){
		cin>>c>>d;
		c--;
		d--;
		s[c].insert(d);
	}
	sort(b,b+m,[](aaa gg,aaa hh){
		return gg.val>hh.val;
	});
	for(int i=0;i<n;i++){
		int po=0;
		while(po<m&&s[i].find(b[po].idx)!=s[i].end()) po++;
		if(po<m) ans=max(ans,a[i]+b[po].val);
	}
	cout<<ans;
	return 0;
}

cin >> n >> m >> l;

    vl a(n), b(m);
    rep(i, n) cin >> a[i];
    rep(i, m) cin >> b[i];
    vector<multiset<int>> x(m);
    rep(i, l) {
        int u, v; cin >> u >> v; --u, --v;
        x[v].insert(a[u]);
    }

    vpll p;
    rep(i, m) p.pb({b[i], i});

    sort(rall(p));
    ll res = -1e18;
    debug(p)
    multiset<int> ms; rep(i, n) ms.insert(a[i]);
    rep(i, m) {
        if(x[p[i].se].empty()) {
            chkmax(res, p[i].fi + *ms.rbegin()); continue;
        }
        if(x[p[i].se].size()==n) continue;

        multiset<int> chenSuX;
        for(auto &h: x[p[i].se]) {
            chenSuX.insert(h);
            ms.erase(ms.find(h));
        } 
        if(!ms.empty()) {
            chkmax(res, p[i].fi + *ms.rbegin());
            for(auto &h: chenSuX) ms.insert(h);
        }

    }

    cout << res << nl;