#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0;i<((int)(n));i++)
#define reg(i,a,b) for(int i = ((int)(a));i<=((int)(b));i++)
#define irep(i,n) for(int i = ((int)(n)-1);i>=0;i--)
#define ireg(i,a,b) for(int i = ((int)(b));i>=((int)(a));i--)
typedef long long ll;
typedef pair<ll, ll> mp;
ll mod = 1e9+7;
//LLONG_MIN

/*
*/

ll n,ans=0;
string s;

int main(void){
	cin>>n>>s;
	rep(i,n){
		if(s[i]=='M'){
			reg(j,1,n){
				if(i-j<0 || i+j>n-1)break;
				if(s[i-j]=='U' && s[i+j]=='G')ans++;
			}
		}
	}
	cout<<ans<<endl;
	return 0;
}