#include <iostream>
#include <string>
using namespace std;
int main(){
	string St,Sam("yukicoder");
	cin>>St;
	int x=0,y=0;
	while(x==0){
		if(St[y]==Sam[y]){
			y++;
		}else{
			cout<<Sam[y]<<endl;
			x=1;
		}
	}
	return 0;
}