import sys

def solve():
    N = int(input())
    hako = [sorted([int(i) for i in input().split()]) for j in range(N)]
    hako.sort()

    inf = 10**9

    dp = [1] * N

    for i in range(N - 2, -1, -1):
        for j in range(i + 1, N):
            if is_larger(hako[i], hako[j]):
                dp[i] = max(dp[i], dp[j] + 1)

    ans = max(dp)

    print(ans)

def is_larger(a, b):
    return all(ai < bi for ai, bi in zip(a, b))

def debug(x, table):
    for name, val in table.items():
        if x is val:
            print('DEBUG:{} -> {}'.format(name, val), file=sys.stderr)
            return None

if __name__ == '__main__':
    solve()