n = int(input())
A = [[] for _ in range(n)]
for _ in range(n):
    l = list(map(str, input().split()))
    for e, k in enumerate(l):
        A[e].append(k)

ret = []
for e, a in enumerate(A):
    s = set(a)
    if s == {'-', 'nyanpass'}:
        ret.append(e)

if len(ret)==1:
    print(ret[0]+1)
else:
    print(-1)