#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <deque>
#include <queue>
#include <array>
#include <set>
#include <map>
#include <cmath>
#include <algorithm>
#include <numeric>
#include <cassert>
#include <utility>
#include <functional>

using namespace std;
using lli = long long int;
template<class T, class U> void init_n(vector<T>& v, size_t n, U x) 
{ v = vector<T>(n, x); }
template<class T> void init_n(vector<T>& v, size_t n) { init_n(v, n, T()); }
template<class T> void read_n(vector<T>& v, size_t n, size_t o = 0) 
{ v = vector<T>(n+o); for (lli i=o; i<n+o; ++i) cin >> v[i]; }
template<class T> void read_n(T a[], size_t n, size_t o = 0)
{ for (lli i=o; i<n+o; ++i) cin >> a[i]; }
template<class T> T gabs(const T& x) { return max(x, -x); }
#define abs gabs

lli n; string s;
int main() {
  cin >> n >> s;
  lli ans = 0;
  for (lli d=1; 2*d<n; ++d) {
    for (lli i=0; i+2*d<n; ++i) {
      if (s[i]=='U' && s[i+d]=='M' && s[i+2*d]=='G') ++ans;
    }
  }
  cout << ans << '\n';
  return 0;
}