def II():return int(input())
def SI():return str(input())
def MI():return map(int,input().split())
def MS():return map(str,input().split())
def LI():return list(map(int,input().split()))
def LS():return list(map(str,input().split()))
s=list(SI())
a="yukicoder"
print(a[s.index("?")])