#include<iostream>
using namespace std;
string s;
int ans,n;
main()
{
    cin>>n>>s;
    for(int i=0;i<n;i++)
    {
        if(s[i]!='M')continue;
        for(int j=1;i-j>=0&&i+j<n;j++)
        {
            if(s[i-j]=='U'&&s[i+j]=='G')ans++;
        }
    }
    cout<<ans<<endl;
}