#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
using PL = pair<ll, ll>;
// Welcome to my source code!

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