#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

//INSERT ABOVE HERE
signed main(){
  Int n;
  cin>>n;
  string s;
  cin>>s;
  Int cnt=0;
  for(Int i=0;i<n;i++){
    for(Int k=i+2;k<n;k+=2){
      Int j=(i+k)>>1;
      if(s[i]=='U'&&s[j]=='M'&&s[k]=='G') cnt++;
    }
  }
  cout<<cnt<<endl;
  return 0;
}