Submission #2211817

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Source Code Expand

#include "bits/stdc++.h"
#define in std::cin
#define out std::cout
#define rep(i,N) for(int i=0;i<N;++i)
typedef long long int LL;

std::string s;
int ans;

int main()
{
	in >> s;
	int l = 0, r = s.length() - 1;
	do
	{
		if (s[l] != s[r])
		{
			if (s[l] != 'x' && s[r] != 'x')
			{
				out << -1 << std::endl;
				return 0;
			}
			++ans;
			if (s[l] == 'x') ++l;
			else if (s[r] == 'x') --r;
		}
		else
		{
			++l; --r;
		}
	} while (l < r);
	out << ans << std::endl;
	return 0;
}

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