#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
    int n; cin>>n;
    string s; cin>>s;
    int ans=0;
    for(int i=0; i<n; i++){
        if(s[i]!='M') continue;
        for(int j=1; i-j>=0 && i+j<n; j++){
            if(s[i-j]=='U' && s[i+j]=='G'){
                ans++;
            }
        }
    }
    cout<<ans<<endl;
    return 0;
}