#include <iostream>
#include <string>

using namespace std;

int main(void)
{
	string s;
	cin >> s;
	
	int n = s.size();
	for(int i = n-1; i > 0; i--){
		if((n-i)%3 == 0) s.insert(s.begin()+i, ',');
	}
	cout << s << endl;
	return 0;
}