n = int(input())
cnt = [0] * n
for i in range(n):
    s = input().split()
    for j, k in enumerate(s):
        if k == 'nyanpass':
            cnt[j] += 1
if cnt.count(n - 1) != 1:
    print(-1)
else:
    print(cnt.index(n - 1) + 1)