#include <bits/stdc++.h>
using namespace std;

int main() {
    string s;
    cin >> s;
    reverse(s.begin(), s.end());
    stack<char> stk;
    for (int i = 0; i < s.length(); ++i) {
        stk.push(s[i]);
        if (i % 3 == 2 && i != s.length() - 1) stk.push(',');
    }
    while (!stk.empty()) {
        cout << stk.top();
        stk.pop();
    }
    cout << endl;
    return 0;
}