N = int(input())
S = [list(input()) for i in range(N)]

X = []
Y = []
for i in range(N):
    for j in range(i):
        if S[i][j] == "-":
            X.append(i)
            Y.append(j)

def win(S):
    wins = [[] for i in range(N)]
    for i in range(N):
        count = 0
        for j in range(N):
            if S[i][j] == "o":
                count += 1
        wins[count].append(i)

    num = 1
    for i in range(N)[::-1]:
        if 0 in wins[i]:
            return num
        if wins[i] != []:
            num += 1
ans = win(S) if len(X) == 0 else N

for i in range(1<<len(X)):
    S2 = S[:]
    for j in range(len(X)):
        x,y = X[j],Y[j]
        if i >> j & 1:
            S2[x][y] = "o"
            S2[y][x] = "x"
        else:
            S2[x][y] = "x"
            S2[y][x] = "o"
    ans = min(ans,win(S2))
print(ans)