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

int main(){
    string N,S="";
    int cnt=0;
    cin >> N;
    for(int i=0;i<N.size();i++){
        cnt++;
        if(cnt == 4){
            S = "," + S;
            cnt = 1;
        }
        S = N[N.size()-1-i] + S;
    }
    cout << S <<  endl;
}