#include <iostream>
using namespace std;
const int INF = 1e9 + 7;

int main()
{
    string s;
    cin >> s;
    int n = s.size();
    for (int i = n - 3; i > 0; i -= 3)
    {
        s.insert(s.begin() + i, ',');
    }
    cout << s << endl;
}