#include <iostream>
#include <string>
using namespace std;

int main()
{
    int n; cin>>n;
    string s; cin>>s;

    long res=0;
    for(int i=0; i+2<n; ++i) if (s[i]=='U')
        for(int k=1; i+k+k<n; ++k) if (s[i+k]=='M' and s[i+k+k]=='G')
            ++res;
    cout<<res<<endl;
}