n = int(input())
S = [list(input()) for _ in range(n)]
win = 0
for j in range(1, n):
    if S[0][j] == "-":
        S[0][j] = "o"
        S[j][0] = "x"
    if S[0][j] == "o":
        win += 1

lst = []    
for i in range(1, n):
    for j in range(i + 1, n):
        if S[i][j] == "-":
            lst.append((i, j))
ans = n
l = len(lst)
for bit in range(1 << l):
    for i in range(l):
        if bit >> i & 1:
            S[lst[i][0]][lst[i][1]] = "o"
            S[lst[i][1]][lst[i][0]] = "x"
            
    se = {win}
    for i in range(1, n):
        tot = 0
        for j in range(n):
            if S[i][j] == "o":
                tot += 1
        se.add(tot)
    ls = sorted(se, reverse = True)
    ans = min(ans, ls.index(win) + 1)
print(ans)