N = int(input())
tbd = []
win = [0] * N
for i in range(N):
    for j, s in enumerate(input()):
        if s == 'o':
            win[i] += 1
        elif s == '-':
            if not (j, i) in tbd:
                tbd.append((i, j))
n = len(tbd)
ans = float('inf')
if n != 0:
    for bm in range(1 << n):
        win_tmp = [0] * N
        for b in range(n):
            if bm & (1 << b) != 0:
                win_tmp[tbd[b][0]] += 1
            else:
                win_tmp[tbd[b][1]] += 1
        total_win = win[0] + win_tmp[0]
        tws = set([win[i] + win_tmp[i] for i in range(N)])
        tmp = 1
        for tw in tws:
            if total_win < tw:
                tmp += 1
        ans = min(ans, tmp)
else:
    tws = set([win[i] for i in range(N)])
    tmp = 1
    for tw in tws:
        if win[0] < tw:
            tmp += 1
    ans = min(ans, tmp)
print(ans)