#coding:utf-8

N=input()
S=[raw_input().split() for i in range(N)]

cnt=[]
for u in S:
	for r,t in enumerate(u):
		if t=='nyanpass':
			cnt.append(r+1)
			
if cnt:
	if len(set(cnt))==1:
		print cnt[0]
	else:
		print -1
else:
	print -1