N = int(input())
L = [input().split() for _ in range(N)]

X = [m+1 for m in range(N) for n in range(N) if L[n][m] == '-' or L[n][m] == 'nyanpass']
Y = [n for n in range(N) if X.count(n) == 4]

print([-1, *Y][len(Y) == 1])