#include <bits/stdc++.h>
using namespace std;

signed main(){
    string s;cin>>s;
    reverse(s.begin(),s.end());
    string t;
    for(int i=0;i<s.size();i++){
        t+=s[i];
        if(i%3==2&&i+1!=s.size())t+=',';
    }
    reverse(t.begin(),t.end());
    cout<<t<<endl;
}