#include <stdio.h>
#include <string.h>

int main(){
	char *ans = "yukicoder";
	char *str;
	scanf("%s",str);
	int len = strlen(ans);
	
	while(*str != '\0'){
		if(*ans != *str){
			printf("%s",*ans);
			return 0;
		}
		ans++;
		str++;
	}
}