N = int(input())
greetings = [input().split() for x in range(N)]
word = "nyanpass"
greetings = list(map(lambda *xs:xs,*greetings))
renchon = -1
is_renchon = []
for idx,greeting in enumerate(greetings):
    if len(set(greeting)) == 2 and word in greeting:
        is_renchon.append(idx + 1)
        if len(is_renchon) > 1:
            break
else:
    if is_renchon:
        renchon = is_renchon[0]
print(renchon)