#include <iostream>
using namespace std;
int main(void) {
	string s, ans = "";
	cin >> s;
	for (int i = s.size() - 1; i >= 0; --i) {
		int diff = s.size() - 1 - i;
		if (diff != 0 && diff % 3 == 0) 
			ans = ',' + ans;
		ans = s[i] + ans;
	}
	cout << ans << endl;
	return 0;
}