#include <bits/stdc++.h>
using namespace std;;
#define ll long long
#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define FORR(i, m, n) for(int i = m;i >= n;i--)
#define INF 1<<30
#define LINF 1LL<<62
#define all(x) (x).begin(), (x).end()
const int MOD = 1000000007;
 
typedef pair<int, int> P;
typedef pair<ll, ll> LP;
typedef pair<int, P> PP;
typedef pair<ll, LP> LPP;

int main(){
    ll n;cin >> n;
    string s; cin>> s;
    ll ans= 0;
    REP(i,n){
        FOR(j,i,n){
            if(2 * j - i >= n) continue;
            if(s[i] == 'U' && s[j] == 'M' && s[2 * j - i] == 'G') ans++;
        }
    }
    cout << ans << endl;

}