def read_data():
    N = int(input())
    xyz = []
    for _ in range(N):
        x, y, z = map(int, input().split())
        xyz.append(x*10**16 + y*10**8 + z)
        xyz.append(x*10**16 + z*10**8 + y)
        xyz.append(y*10**16 + x*10**8 + z)
        xyz.append(y*10**16 + z*10**8 + x)
        xyz.append(z*10**16 + x*10**8 + y)
        xyz.append(z*10**16 + y*10**8 + x)
    return N, xyz

def solve(N, xyz):
    xyz.append(0)
    xyz.sort()
    dp = [0] * (N * 6 + 1)
    for idx, val in enumerate(xyz):
        tmp = 0
        for idx2, val2 in enumerate(xyz[:idx]):
            if val2 < val and tmp < dp[idx2]:
                tmp = dp[idx2]
        dp[idx] = tmp + 1
    return max(dp) - 1

N, xyz = read_data()
print(solve(N, xyz))