#include <bits/stdc++.h>
using namespace std;
using lint = long long;
template<class T = int> using V = vector<T>;
template<class T = int> using VV = V< V<T> >;

int main() {
  cin.tie(nullptr); ios::sync_with_stdio(false);
  int n; cin >> n;
  string s; cin >> s;
  int res = 0;
  for (int x = 1; x <= n; ++x) {
    for (int j = 0; j < n; ++j) {
      int i = j - x, k = j + x;
      if (i < 0 or k >= n) continue;
      res += s[i] == 'U' and s[j] == 'M' and s[k] == 'G';
    }
  }
  cout << res << '\n';
}