#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000000000000


int main(){
	
	int N;
	cin>>N;
	
	string S;
	cin>>S;
	
	int ans = 0;
	
	rep(i,S.size()){
		if(S[i]!='M')continue;
		
		rep(j,S.size()){
			if(i-j<0||i+j>=S.size())break;
			if(S[i-j]=='U'&&S[i+j]=='G')ans++;
		}
	}
	
	cout<<ans<<endl;
	
    return 0;
}