#include <iostream>
#include <string>
using namespace std;

int main() {
	int N;
	cin >> N;
	string S;
	cin >> S;
	int ans = 0;
	for (int i = 0; 2 * (i + 1) < N; ++i) {
		for (int j = 0; 2 * (i + 1) + j < N; ++j) {
			if (S[j] == 'U' && S[i + j + 1] == 'M' && S[2 * (i + 1) + j] == 'G') ++ans;
		}
	}
	cout << ans;
}