#include <bits/stdc++.h>

using namespace std;

using int64 = long long;


int main() {
  string S;
  cin >> S;
  int add = 0;
  string T;
  for(int i = S.size() - 1; i >= 0; i--) {
    ++add;
    T += S[i];
    if(add % 3 == 0 && i) {
      T += ",";
    }
  }
  reverse(T.begin(), T.end());
  cout << T << endl;
}