import sys
sys.setrecursionlimit(10000)
import itertools

n = int(input())
X = [0] * n
Y = [0] * n
Z = [0] * n
for i in range(n):
    X[i], Y[i], Z[i] = map(int, input().split())

def ok(i, j):
    A = (X[i], Y[i], Z[i])
    B = (X[j], Y[j], Z[j])
    for C in itertools.permutations(B):
        if all(a < c for a, c in zip(A, C)):
            return True

edges = [[] for _ in range(n)]
for i in range(n):
    for j in range(n):
        if ok(i, j):
            edges[i].append(j)

dp = [-1] * n

def dfs(pos):
    dp[pos] = 0
    for npos in edges[pos]:
        if dp[npos] == -1:
            dfs(npos)
        dp[pos] = max(dp[pos], dp[npos] + 1)

for i in range(n):
    if dp[i] != -1:
        continue
    dfs(i)

print(max(dp) + 1)