#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
using ll = long long;

int main() {
    string s;
    cin >> s;
    int n = s.size();

    string r;
    for (int i = 0; i < n; i++) {
        r += s[i];
        if ((n - 1 - i) % 3 == 0 && i != n - 1) r += ',';
    }

    cout << r << endl;

    return 0;
}