import sys


def input(): return sys.stdin.readline().rstrip()


def main():
    N = int(input())
    s = [list(input()) for i in range(N)]

    ans = N
    A = []
    for i in range(N):
        for j in range(i):
            if s[j][i] == '-':
                A.append((j, i))

    for i in range(1 << len(A)):
        for j in range(len(A)):
            s[A[j][0]][A[j][1]] = 'o' if i & (1 << j) else 'x'
            s[A[j][1]][A[j][0]] = 'x' if i & (1 << j) else 'o'

        z = [a.count('o') for a in s]
        k = sorted(set(z), reverse=True)
        ans = min(ans, k.index(z[0])+1)

    print(ans)


if __name__ == '__main__':
    main()