#include <bits/stdc++.h>
#define int long long
#define double long double
using namespace std;
const int MOD =  1000000007;
const int INF = 1e11;
using Graph = vector<vector<int>>;


signed main(){
  int N;
  string S;
  cin >> N >> S;

  int ans = 0;
  for( int i = 0; i < S.size(); i++ ){
    for( int k = i+2; k < S.size(); k++ ){
      if( (i+k)%2 == 1 ) continue;
      if( S[i] == 'U' && S[(i+k)/2] == 'M' && S[k] == 'G' ) ans++;
    }
  }
  cout << ans << endl;
}