#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define printVec(v) printf("{"); for (const auto& i : v) { std::cout << i << ", "; } printf("}\n");
#define ALL(obj) (obj).begin(), (obj).end();
#define debug(x) cout << #x << ": " << x << '\n';
#define degreeToRadian(deg) (((deg)/360)*2*M_PI)
#define radianTodegree(rad) (((rad)/2/M_PI)*360)
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
using namespace std;
using P = pair<int,int>;
using ll = long long;
const ll INF = 1LL<<60;
const int MOD = 1e9 + 7;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

//cin.tie(0);ios::sync_with_stdio(false);
//cout << fixed << setprecision(15) << y << endl;
int main() {
  int N;
  string S;
  cin >> N >> S;

  int cnt = 0;
  for (int i = 1; i < N - 1; i++) {
    if (S[i] == 'M') {
      string s = S.substr(i + 1, i);
      string ss = S.substr(i - s.size(), s.size());

      for (int j = 0; j < s.size(); j++) {
	if (s[j] == 'U' && ss[ss.size() - 1 - j] == 'G') cnt++;
	if (s[j] == 'G' && ss[ss.size() - 1 - j] == 'U') cnt++;	
      }
    }
  }

  cout << cnt << endl;
  return 0;
}