import copy
N = int(input())
S = [list(input()) for _ in range(N)]
A = []
for i in range(N-1):
    for j in range(i+1,N):
        if S[i][j]=="o" and S[j][i]=="-":
            S[j][i] = "x"
        elif S[i][j]=="x" and S[j][i]=="-":
            S[j][i] = "o"
        elif S[i][j]=="-" and S[j][i]=="o":
            S[i][j] = "x"
        elif S[i][j]=="-" and S[j][i]=="x":
            S[i][j] = "o"
        if S[i][j]=="-":
            A.append((i,j))
ans = N
for i in range(1<<len(A)):
    B = copy.deepcopy(S)
    for j in range(len(A)):
        y,x = A[j]
        if (i>>j)&1:
            B[y][x] = "o"
            B[x][y] = "x"
        else:
            B[y][x] = "x"
            B[x][y] = "o"
    C = [0]*N
    for k in range(N):
        C[k] = B[k].count("o")
    a = C[0]
    C = sorted(list(set(C)),reverse=True)
    cnt = C.index(a)+1
    ans = min(ans,cnt)
print(ans)