#include <bits/stdc++.h>

using namespace std;

int main() {
    string s;
    cin >> s;

    reverse(s.begin(), s.end());
    string ans;
    for (int i = 0; i < (int) s.length(); ++i) {
        ans += s[i];
        if (i % 3 == 2 and i != s.length() - 1) ans += ',';
    }

    reverse(ans.begin(), ans.end());
    cout << ans << endl;
    return 0;
}