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

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

	string a = "";
	int c = 0;
	for (int i = s.size()-1; 0 <= i; i--) {
		if (c == 3) {
			a.push_back(',');
			c = 0;
		}

		a.push_back(s.at(i));
		c++;
	}

	for (int i = a.size()-1; i >= 0; i--) {
		cout << a.at(i);
		if (i == 0) {
			cout << endl;
		}
	}
}