import bisect
import copy
import decimal
import fractions
import heapq
import itertools
import math
import random
import sys
from collections import Counter, deque,defaultdict
from functools import lru_cache,reduce
from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max
def _heappush_max(heap,item):
    heap.append(item)
    heapq._siftdown_max(heap, 0, len(heap)-1)
def _heappushpop_max(heap, item):
    if heap and item < heap[0]:
        item, heap[0] = heap[0], item
        heapq._siftup_max(heap, 0)
    return item
from math import gcd as GCD
read=sys.stdin.read
readline=sys.stdin.readline
readlines=sys.stdin.readlines

N=int(readline())
S=[list(readline().rstrip()) for i in range(N)]
ans=float('inf')
lst=[(i,j) for j in range(1,N) for i in range(j) if S[i][j]=='-']
for bit in range(1<<len(lst)):
    SS=[[S[i][j] for j in range(N)] for i in range(N)]
    for b in range(len(lst)):
        i,j=lst[b]
        if bit>>b&1:
            SS[i][j]='o'
            SS[j][i]='x'
        else:
            SS[j][i]='o'
            SS[i][j]='x'
    win={ss.count('o') for ss in SS}
    win=sorted(list(win),reverse=True)
    ans=min(ans,win.index(SS[0].count('o'))+1)
print(ans)