n = int(input())
a = [["" for i in range(n)] for i in range(n)]
for i in range(n):
	s = list(input().split())
	for j in range(n):
		a[j][i] = s[j]
kouho = list(range(n))
for i in range(n):
	for j in range(n):
		if a[i][j] == "-":
			pass
		elif a[i][j] != "nyanpass":
			kouho.remove(i)
			break
if len(kouho) >= 2:
	print(-1)
elif len(kouho) == 0:
	print(-1)
else:
	print(kouho[0]+1)