#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define fi first
#define se second
#define FOR(i,n) for(int i = 0;i<n;i++)
#define rep(i,s,n) for(int i = s;i<n;i++)
#define rrep(i,s,n) for(int i = (n)-1;i>=(s);i--)
#define all(v) (v).begin(),(v).end()
#define chmin(a,b) a=min((a),(b))
#define chmax(a,b) a=max((a),(b))
#define endl '\n'
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0)
typedef long long ll;
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
const ll MOD=1000000007,INF=1ll<<60;
typedef vector<vint>vvint;

int N;
string s;
int ans=0;

signed main() {
    IOS();
    cin>>N>>s;
    rep(i,0,N){
        if(s[i]!='M')continue;
        int l=i-1,r=i+1;
        while(l>=0&&r<N){
            if(s[l]=='U'&&s[r]=='G')ans++;
            l--;r++;
        }
    }
    cout<<ans<<endl;
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    return 0;
}