#include <iostream>
#include<string>
using namespace std;
int main() {
    string s;
    string result;
    cin>>s;
    int count=0;
    for(int i=s.size()-1;i>=0;i--){
        result=s[i]+result;
        count++;
        if(count%3==0&&count!=s.size()){
            result=','+result;
        }
    }
    cout<<result;
    return 0;
}