#include<bits/stdc++.h>
#define F first
#define S second
#define MP make_pair
#define pb push_back
#define endl '\n'

using namespace std;

typedef long long LL;
typedef pair< int, int > P;
typedef pair< LL, LL > LP;
typedef pair< int, P > iP;
typedef pair< P, P > PP;

static const int INF = INT_MAX;
static const LL LINF = LLONG_MAX;
static const int MIN = INT_MIN;
static const LL LMIN = LLONG_MIN;
static const int MOD = 1000000007;

int dx[] = {0, -1, 1, 0};
int dy[] = {-1, 0, 0, 1};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int n;
    string s;
    cin >> n >> s;
    int cnt = 0;

    for( int i = 0; i < s.size(); ++i ) {
        for( int j = i + 1; j + ( j - i ) < s.size(); ++j ) {
            if( s[i] == 'U' && s[j] == 'M' && s[j + ( j - i )] == 'G' ) ++cnt;

        }
    }

    cout << cnt << endl;
    return 0;
}