import numpy as np

N = int(input())
S = np.array([[s == '.' for s in input()] for _ in range(N)])


def solve(S):
    """左詰め横並べ"""
    left = S[:, 0].copy()
    right = S[:, -1].copy()
    res = 0
    for i in range(N):
        if np.all(S[i, 1:-1]):
            if S[i, 0]:
                res += 1
                left[i] = False
            elif S[i, -1]:
                res += 1
                right[i] = False
    if np.all(left[1:-1]) and (left[0] or left[-1]):
        res += 1
    if np.all(right[1:-1]) and (right[0] or right[-1]):
        res += 1

    return res


ans = 0
# ぐるっと一周パターン
if np.all(S[0, :]) and np.all(S[:, 0]) and np.all(S[-1, :]) and np.all(S[:, -1]):
    ans = 4

for i in range(4):
    ans = max(ans, solve(S))
    # 回す
    S = np.fliplr(S.T)
print(ans)