#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <math.h>
#include <string.h>

int main()
{
	char str[10] = "";
	char yukicoder[] = "yukicoder";

	scanf("%s", str);

	for (int i = 0;yukicoder[i] != '\0';i++)
	{
		if (str[i] != yukicoder[i])
		{
			printf("%c", yukicoder[i]);
			return 0;
		}
	}

	return 0;
}