from copy import deepcopy
N = int(input())
M = (N-1) * N // 2
s = [list(input()) for _ in range(N)]
P = []
for i in range(1,N):
    for j in range(i):
        P.append((i,j))
ans = 100
for bit in range(2**M):
    S = deepcopy(s)
    x = bit
    for i in range(M):
        a,b = P[i]
        if S[a][b] != '-':
            pass
        elif x & 1:
            S[a][b] = 'o'
            S[b][a] = 'x'
        else:
            S[b][a] = 'o'
            S[a][b] = 'x'
        x >>= 1
    cnt = [0] * N
    T = []
    for i in range(N):
        for j in range(N):
            if S[i][j] == 'o':
                cnt[i] += 1
        T.append(cnt[i])
    T.sort(reverse=True)
    for i in range(N):
        if T[i] == cnt[0]:
            ans = min(ans, i+1)
            break
print(ans)