#include <iostream>
using namespace std;
int main(void){
    string s;
    cin >> s;
    int n = (s.size()-1) / 3;
    int p = s.size()-3;
    for (int i = 0; i < n; i++) {
        s.insert(p - 3 * i, ",");
    }
    cout << s << endl;
}