#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
typedef pair<int ,P> P3;
typedef pair<P ,P> PP;
const ll MOD = ll(1e9+7);
const int IINF = INT_MAX;
const ll LLINF = LLONG_MAX;
const int MAX_N = int(1e6 + 5);
const double EPS = 1e-6;
const int di[] = {0, 1, 0, -1}, dj[] = {1, 0, -1, 0};
#define REP(i, n) for (int i = 0; i < n; i++)
#define REPR(i, n) for (int i = n; i >= 0; i--)
#define SORT(v) sort((v).begin(), (v).end())
#define SORTR(v) sort((v).rbegin(), (v).rend())
#define ALL(v) (v).begin(), (v).end()



int main() {
    int n, ans = 0;
    string s;
    cin >> n >> s;
    REP(i,n){
        if(s[i]=='M'){
            for(int j=1;i-j>=0 && i+j<n;j++){
                if(s[i-j]=='U' && s[i+j]=='G') ans++;
            }
        }
    }
    cout << ans << endl;
    return 0;
}