#include "bits/stdc++.h"
#define Rep(i,n) for(int i=0;i<n;i++)
#define For(i,n1,n2) for(int i=n1;i<n2;i++)
#define REP(i,n) for(ll i=0;i<n;i++)
#define FOR(i,n1,n2) for(ll i=n1;i<n2;i++)
#define put(a) cout<<a<<endl;
#define all(a)  (a).begin(),(a).end()
#define SORT(c) sort((c).begin(),(c).end())
#define TDARRAY(int,a,n,m) vector<vector<int>> a(n,vector<int>(m,0));
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
template<class T> inline bool chmax(T& a, T b) {if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T& a, T b) {if(a>b){a=b;return 1;}return 0;}

int n;
string s;

int main(){
    cin >> n >> s;
    vector<int> a;
    vector<int> b;
    vector<int> c;
    
    Rep(i,n){
        if(s[i]=='U')a.push_back(i);
        if(s[i]=='M')b.push_back(i);
        if(s[i]=='G')c.push_back(i);
    }
    vector<int> d(10000,0);
    REP(i,a.size()){
        REP(j,c.size()){
            if(a[i]<c[j])d[a[i]+c[j]]++;
        }
    }
    ll res = 0;
    REP(i,b.size()){
        res+=d[2*b[i]];
    }
    put(res);
    return 0;
}