#include <iostream>
#include <fstream>
#include <string>
#include <vector>

int main(void) {

	//std::ifstream inf("Text.txt");	std::cin.rdbuf(inf.rdbuf());
	
	std::string A = "yukicoder";
	std::string S;
	std::cin >> S;
	std::cout << A[(int)S.find('?')] << std::endl;

	return 0;
}