#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;

void solve() {
  string s, ans;
  cin >> s;
  reverse(s.begin(), s.end());
  rep(i, 0, s.size()) {
    ans += s[i];
    if ((i + 1) % 3 == 0 && i+1 != s.size() ) ans += ",";
  }
  reverse(ans.begin(), ans.end());
  cout << ans << endl;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
  getchar();
}