```

include “bits/stdc++.h”

using namespace std;

int n, res;
string s;

int main() {
cin >> n;
string s;
cin >> s;
int len = s.size();

for (int i = 0, j = 0; i < len; i ++) {
    j = i;
    while (i < len && s[i] == 'x') i ++;
    if (i - j >= 3) res = res + i - j - 2;
}

cout << res << endl;
return 0;

}```