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

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

  int ans = 0;
  for (int i = 0; i < n; ++i) {
    for (int j = i + 1; j < n; ++j) {
      int k = j - i + j;
      if (k >= n) continue;
      if (s[i] == 'U' && s[j] == 'M' && s[k] == 'G') ans++;
    }
  }
  cout << ans << '\n';
  return 0;
}