tijie

10ms

#include<bits/stdc++.h>
using namespace std;
int main() {
	string s;
    cin >> s;
    long long n = 0, sum = 0;
    for (int i = 0; i < s.size(); i++) {
        if (s[i] == 'z') n++;
        else if (s[i] == 'y') sum += n * (n - 1) / 2;
    }
    cout << sum;
	return 0;
}