n = int(input())
l = [input().split() for _ in range(n)]

l2 = []
for i in range(n):
    l3 = []
    for j in range(n):
        l3.append(l[j][i])
    l2.append(l3)

l4 = []
for i in range(len(l2)):
    if len(set(l2[i])) == 2 and '-' in l2[i] and 'nyanpass' in l2[i]:
        l4.append(i+1)

if len(l4) == 1:
    print(*l4)
else:
    print(-1)