#include <iostream>
#include <string>

void solve() {
    int n;
    std::string s;
    std::cin >> n >> s;

    int ans = 0;
    for (int l = 1; l < n; ++l) {
        for (int i = 0; i + l * 2 < n; ++i) {
            int j = i + l,
                k = i + l * 2;
            if (s[i] == 'U' && s[j] == 'M' && s[k] == 'G') ++ans;
        }
    }

    std::cout << ans << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}