#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

int main() {
    int n;
    cin >> n;
    string s;
    cin >> s;

    int ans = 0;

    rep(i,n){
        int j = 1;
        while(i + j + j < n){
            if(s[i] == 'U' && s[i+j] == 'M' && s[i+j+j] == 'G')ans++;
            j++;
        }
    }

    cout << ans << endl;
    return 0;
}