def dfs(depth):
    if depth == len(yet_coor):
        count = 0
        k_win = win_count[0] + w_list[0]
        pre_list = []
        for i, j in list(zip(win_count, w_list))[1:]:
            if k_win < i + j and i + j not in pre_list:
                count += 1
                pre_list.append(i + j)
        return count + 1

    r, c = yet_coor[depth]
    w_list[r] += 1
    tmp_rank = dfs(depth + 1)
    w_list[r] -= 1
    w_list[c] += 1
    tmp_rank = min(tmp_rank, dfs(depth + 1))
    w_list[c] -= 1
    return tmp_rank

n = int(input())
matrix = [input() for i in range(n)]

win_count = []
yet_coor = []
for i, row in enumerate(matrix):
    win = 0
    for j, cell in enumerate(row):
        if cell == 'o':
            win += 1
        if i < j:
            if cell == '-':
                yet_coor.append([i, j])
    win_count.append(win)

w_list = [0] * n

print(dfs(0))