n = int(input())
s = [input().strip() for _ in range(n)]

current_wins = [0] * n
for i in range(n):
    for j in range(n):
        if i == j:
            continue
        if s[i][j] == 'o':
            current_wins[i] += 1

# Calculate team 0's maximum possible wins by winning all remaining matches
remaining_0 = 0
for j in range(n):
    if j == 0:
        continue
    if s[0][j] == '-':
        remaining_0 += 1
max_wins0 = current_wins[0] + remaining_0

# Collect remaining matches between other teams (i, j where i < j and neither is 0)
remaining_matches = []
for i in range(n):
    for j in range(i + 1, n):
        if i == 0 or j == 0:
            continue
        if s[i][j] == '-':
            remaining_matches.append((i, j))

m = len(remaining_matches)
min_rank = float('inf')

# Generate all possible outcomes for the remaining matches
for mask in range(1 << m):
    wins = current_wins.copy()
    wins[0] = max_wins0  # Team 0's wins are fixed
    
    # Apply the current mask to determine outcomes of remaining matches
    for k in range(m):
        i, j = remaining_matches[k]
        if (mask >> k) & 1:
            wins[j] += 1  # j wins
        else:
            wins[i] += 1  # i wins
    
    # Calculate rank for team 0
    sorted_wins = sorted(wins, reverse=True)
    rank = sorted_wins.index(wins[0]) + 1
    if rank < min_rank:
        min_rank = rank

print(min_rank)