#include <iostream>
#include <string> 
#include <algorithm>

using namespace std;
int main(void){
    // Your code here!
    string N;
    cin >> N;
    
    reverse(N.begin(),N.end());
    
    string S = "";
    for(int i = 0; i < N.size(); i++){
        S.push_back(N[i]);
        if(i%3 == 2 and i != N.size() - 1){
            S.push_back(',');
        }
    }
    
    for(auto itr = S.rbegin(); itr != S.rend(); itr++){
        cout << *itr;
    }
    cout << endl;
}