n = int(input())
s = [list(input()) for _ in range(n)]

games = []

for i in range(n):
    for j in range(n):
        if s[i][j] == "-":
            games.append((i, j))

m = len(games)
current_rank = n

for bit in range(1 << m):
    win = [0] * n
    for i in range(n):
        for j in range(n):
            if s[i][j] == "o":
                win[i] += 1

    for k in range(m):
        i, j = games[k]
        if (bit >> k) & 1:
            win[i] += 1
        else:
            win[j] += 1

    calc_win = win[0]
    rank = 1
    for t in range(n):
        if win[t] > calc_win:
            rank += 1

    current_rank = min(current_rank, rank)

print(current_rank)