import itertools
N = int(input())
S = [list(input()) for _ in range(N)]

count = 0
for s in S:
    for m in s:
        if m == '-':
            count += 1
    
rg = count//2
WL = ('o','x')
rup = []

for pat in itertools.product(WL, repeat=rg):
    p = list(pat)
    CS = [x[:] for x in S]
    wn = []
    for j in range(N):
        for k in range(N):
            if CS[j][k] == '-':
                wl = p.pop()
                if wl == 'o':
                    CS[j][k] = 'o'
                    CS[k][j] = 'x'
                else:
                    CS[j][k] = 'x'
                    CS[k][j] = 'o'
    for cs in CS:
        w = cs.count('o')
        wn.append(w)
    tw = wn[0]
    swn = list(set(wn))
    wn = sorted(swn, reverse=True)
    rank = wn.index(tw) + 1
    rup.append(rank)
print(min(rup))