#include <cstdio>
#define REP(i,n) for (int i=0;i<(n);i++)
int main(){
	char S[10];
	char T[10]={'y','u','k','i','c','o','d','e','r',0};
	scanf("%s",S);
	REP(i,9){
		if(S[i]!=T[i]){
			printf("%c\n",T[i]);
			break;
		}
	}
	return 0;
}