#include <bits/stdc++.h>

using namespace std;

int main()
{
    std::string N;
    cin >> N;
    std::string ans = "";
    int count = 0;
    for(int i = N.size() - 1; i >= 0; --i) {
        count++;
        ans += N[i];
        if(count % 3 == 0 && i != 0) ans += ',';
    }
    reverse(ans.begin(), ans.end());
    cout << ans << endl;
}