#include <iostream>
#include <string>

int main( void ){
	std::string str;
	std::cin >> str;
	if (str.length() < 4){
		std::cout << str << std::endl;
		return 0;
	}
	int times = str.length() / 3;
	int mod = str.length() % 3;
	int i = 0;
	for(; i < mod; i++){
		std::cout << str[ i ];
	}
	if (mod != 0){
		std::cout << ',';
	}
	std::cout << str[ mod ] << str[ mod + 1 ] << str[ mod + 2 ];
	for(int i = 3; i+mod < str.length(); i+=3){
		std::cout << ',' << str[ i+mod ] << str[ i + mod + 1 ] << str[ i + mod + 2 ];
	}
	std::cout << std::endl;
	return 0;
}