import sys
import math
import functools
import itertools
import copy

def solve():
	N = int(input())
	S = [ input() for _ in range(N) ]

	tmp = copy.deepcopy(S)
	ans_c1 = 0
	for i, s in enumerate(S):
		if '#' not in s[:N-1]:
			ans_c1 += 1
			tmp[i] = (N-1)*'#'+ tmp[i][N-1]
	else:
		st = list(zip(*tmp))
		if '#' not in st[0] or '#' not in st[N-1]:
			ans_c1 += 1
	

	tmp = copy.deepcopy(S)
	ans_c2 = 0
	for i, s in enumerate(S):
		if '#' not in s[1:N]:
			ans_c2 += 1
			tmp[i] = tmp[i][0] + (N-1)*'#' 
	else:
		st = list(zip(*tmp))
		if '#' not in st[0] or '#' not in st[N-1]:
			ans_c2 += 1
		
	tmp = list(map(list, zip(*S)))
	ans_r1 = 0
	for i, s in enumerate(list(map(list, zip(*S)))):
		if '#' not in s[:N-1]:
			ans_r1 += 1
			tmp[i] = (N-1)*'#' + tmp[i][N-1]
	else:
		st = list(zip(*tmp))
		if '#' not in st[0] or '#' not in st[N-1]:
			ans_r1 += 1

	tmp = list(zip(*S))
	ans_r2 = 0
	for i, s in enumerate(list(zip(*S))):
		if '#' not in s[1:N]:
			ans_r2 += 1
			tmp[i] = tmp[i][0] + (N-1)*'#' 
	else:
		st = list(zip(*tmp))
		if '#' not in st[0] or '#' not in st[N-1]:
			ans_r2 += 1

	at = sorted([ans_r1, ans_r2, ans_c1, ans_c2])
	
	
	if at[-1] >= 4:
		print(at[-1])
	else:
		if '#' not in S[0] and '#' not in S[N-1] and '#' not in list(zip(*S))[0] and '#' not in list(zip(*S))[N-1]:
			print(4)
		else:
			print(at[-1])
		

if __name__ == "__main__":
	solve()