import sys
input=lambda: sys.stdin.readline().rstrip()
n=int(input())
S=[list(input()) for _ in range(n)]


Und=[]
for i in range(n):
  for j in range(i+1,n):
    if S[i][j]=="-":
      Und.append((i,j))

if not Und:
  Res=set()
  w=0
  for i in range(n):
    wi=0
    for j in range(n):
      if S[i][j]=="o":
        wi+=1
    if i==0:
      w=wi
    elif wi>w:
      Res.add(wi)
  print(len(Res)+1)
else:
  ans=n
  nn=len(Und)
  for i in range(2**nn):
    for j in range(nn):
      if i&(1<<j):
        S[Und[j][0]][Und[j][1]]="o"
        S[Und[j][1]][Und[j][0]]="x"
      else:
        S[Und[j][0]][Und[j][1]]="x"
        S[Und[j][1]][Und[j][0]]="o"
    
    Res=set()
    w=0
    for ii in range(n):
      wi=0
      for j in range(n):
        if S[ii][j]=="o":
          wi+=1
      if ii==0:
        w=wi
      elif wi>w:
        Res.add(wi)
    ans=min(ans,len(Res)+1)
  print(ans)