import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class No00000494_Main2 {
	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	public static void main(String[] args) throws IOException {
		System.out.println("yukicoder".charAt(br.readLine().indexOf("?")));
	}
}