#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main() {
  string N, t;
  cin >> N;
  reverse(N.begin(), N.end());
  for (size_t i = 0, j = 0; i < N.length(); ) {
    if (j == 3) {
      t += ",";
      j = 0;
    } else {
      t += N.substr(i, 1);
      i++;
      j++;
    }

  }
  reverse(t.begin(), t.end());
  cout << t << endl;
}