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

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