#include <bits/stdc++.h>
using namespace std;
#define int long long
int MOD = (int)1e9 + 7;
int INF = (int)2e18;
// Comment out below and program paste

// #include "UnionFind.hpp"
// #include "power.hpp"

signed main() {
    int N;
    cin >> N;
    string S;
    cin >> S;
    int ans = 0;
    for (int i = 1; i < N - 1; i++) {
        if (S[i] != 'M') continue;
        for (int j = 0; i - j >= 0; j++) {
            if (S[i - j] == 'U' && S[i + j] == 'G') ++ans;
        }
    }
    cout << ans << endl;
}