#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define int long long
using namespace std;
typedef pair<int, int> P;
const int mod = 1000000007;
const int INF = 1e18;

signed main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	int n;
	cin >> n;
	string s;
	cin >> s;
	int ans = 0;
	rep(i, 0, n){
		if(s[i] != 'M') continue;
		for(int j = 1; i - j >= 0 && i + j < n; j++){
			if(s[i - j] == 'U' && s[i + j] == 'G') ans++;
		}
	}
	cout << ans << endl;
}