#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n; cin >> n;
    string s; cin >> s;

    int ans = 0;
    for (int step = 1; step <= n/2; ++step) {
        for (int i = 0; i + 2*step < n; ++i) {
            int j = i + step, k = i + 2*step;
            if (s[i] == 'U' && s[j] == 'M' && s[k] == 'G') ++ans;
        }
    }
    cout << ans << endl;
    
    return 0;
}