Codeforces Round 571 (Div. 2) |
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Finished |
Vus the Cossack has two binary strings, that is, strings that consist only of "0" and "1". We call these strings $$$a$$$ and $$$b$$$. It is known that $$$|b| \leq |a|$$$, that is, the length of $$$b$$$ is at most the length of $$$a$$$.
The Cossack considers every substring of length $$$|b|$$$ in string $$$a$$$. Let's call this substring $$$c$$$. He matches the corresponding characters in $$$b$$$ and $$$c$$$, after which he counts the number of positions where the two strings are different. We call this function $$$f(b, c)$$$.
For example, let $$$b = 00110$$$, and $$$c = 11000$$$. In these strings, the first, second, third and fourth positions are different.
Vus the Cossack counts the number of such substrings $$$c$$$ such that $$$f(b, c)$$$ is even.
For example, let $$$a = 01100010$$$ and $$$b = 00110$$$. $$$a$$$ has four substrings of the length $$$|b|$$$: $$$01100$$$, $$$11000$$$, $$$10001$$$, $$$00010$$$.
Since in three substrings, $$$f(b, c)$$$ is even, the answer is $$$3$$$.
Vus can not find the answer for big strings. That is why he is asking you to help him.
The first line contains a binary string $$$a$$$ ($$$1 \leq |a| \leq 10^6$$$) — the first string.
The second line contains a binary string $$$b$$$ ($$$1 \leq |b| \leq |a|$$$) — the second string.
Print one number — the answer.
01100010 00110
3
1010111110 0110
4
The first example is explained in the legend.
In the second example, there are five substrings that satisfy us: $$$1010$$$, $$$0101$$$, $$$1111$$$, $$$1111$$$.
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