#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <numeric>
#include <cassert>
#include <memory>
#include <stack>
#include <set>
#include <map>

#define INF 1000000000
#define MOD 1000000007
typedef long long ll;
typedef unsigned long long ull;
using namespace std;

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

  string n; cin>>n;
  string s;
  int j = 0;
  for(int i = n.size() - 1; i >= 0; i--) {
    if (j % 3 == 0 && j != 0) {
      s += ',';
    }
    s += n[i];
    j++;
  }
  reverse(s.begin(),s.end());
  cout << s << endl;
}