#include <iomanip>
#include <cmath>
#include <sstream>
#include <unordered_map>
#include <unordered_set>
#include <deque>
#include <vector>
#include <bitset>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include<iostream>
#include<map>
#include<algorithm>

using namespace std;

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

	long long int ans = 0;

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

	cout << ans << endl;

	return 0;
}