S=input()
size=len(S)
K=0
i=0
size-=8
y="y"
yukicoder="yukicoder"
while i<size:
	if S[i]==y:
		count=0
		while S[i:i+9]==yukicoder:
			count+=1
			i+=9
		if K<count:
			K=count
	i+=1
print(K)