def dfs(a,s,n):

	if n * n == a:
		rank,x,o = 1,0,0
		for i in range(n):
			if s[0][i] == 'x':
				x += 1
			elif s[0][i] == 'o':
				o += 1
		p = set([])
		for i in range(1,n):
			X,O = 0,0
			for j in range(n):
				if s[i][j] == 'x':
					X += 1
				elif s[i][j] == 'o':
					O += 1
			if O > o:
				p.add(O)
		return len(p) + 1
	y = a // n
	x = a % n

	if s[y][x] != '-':
		return dfs(a + 1,s,n)
	else:
		s[y][x] = 'x'
		s[x][y] = 'o'
		ret = dfs(a + 1,s,n)
		s[y][x] = 'o'
		s[x][y] = 'x'
		ret = min(ret,dfs(a + 1,s,n))
		s[y][x] = s[x][y] = '-'
		return ret
N = int(input())
s = [ list(input()) for i in range(N)]
print(dfs(0,s,N))