#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> l_l;

#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))
//const ll mod = 1000000007;

int main() {
    //cout.precision(10);
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    string S;
    cin >> S;
    int ans = 0;
    for(int center = 1; center < S.size(); center++) {
        if(S[center] != 'M') continue;
        for(int delta = 1; ; delta++) {
            if(center - delta < 0) break;
            if(center + delta >= S.size()) break;
            if(S[center-delta] == 'U' && S[center+delta] == 'G') ans++;
        }
    }
    cout << ans << endl;
    return 0;
}