/* ---------- STL Libraries ---------- */
// IO library
#include <cstdio>
#include <fstream>
#include <iomanip>
#include <ios>
#include <iostream>

// algorithm library
#include <algorithm>
#include <cmath>
#include <numeric>
#include <random>
#include <cstring>

// container library
#include <array>
#include <bitset>
#include <deque>
#include <map>
#include <unordered_map>
#include <queue>
#include <set>
#include <string>
#include <tuple>
#include <vector>
#include <stack>

/* ---------- Namespace ---------- */
using namespace std;

/* ---------- Type ---------- */
using ll = long long;
#define int ll
#define P pair<ll, ll>

/* ---------- Constants  */
const double PI = 3.141592653589793238462643383279;
const ll MOD = 1e9 + 7;
const int INF = 1LL << 55;

/* v-v-v-v-v-v-v-v-v Main Part v-v-v-v-v-v-v-v-v */
signed main() {
    int N;
    string str;
    cin >> N >> str;
    int ret = 0;
    for (int len = 1; 2 * len <= N - 1; len++) {
        for (int i = 0; i < N; i++) {
            int j = i + len;
            int k = j + len;
            if (k >= N) continue;
            if (str[i] == 'U' && str[j] == 'M' && str[k] == 'G') ret++;
        }
    }

    cout << ret << endl;

    return 0;
}