from operator import itemgetter
from itertools import *
from bisect import *
from collections import *
from heapq import *
import sys

sys.setrecursionlimit(10 ** 6)

def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def SI(): return sys.stdin.readline()[:-1]
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
int1 = lambda x: int(x) - 1
def MI1(): return map(int1, sys.stdin.readline().split())
def LI1(): return list(map(int1, sys.stdin.readline().split()))
p2D = lambda x: print(*x, sep="\n")
dij = [(1, 0), (0, 1), (-1, 0), (0, -1)]

class BitMax:
    def __init__(self, n=1005):
        self.inf=10**9
        self.n = n + 3
        self.table = [-self.inf] * (self.n + 1)

    def update(self, i, x):
        i += 1
        while i <= self.n:
            if x > self.table[i]: self.table[i] = x
            i += i & -i

    def max(self, i):
        i += 1
        res = -self.inf
        while i > 0:
            if self.table[i] > res: res = self.table[i]
            i -= i & -i
        return res

def main():
    n=II()
    zxy=defaultdict(list)
    yy=set()
    for xyz in LLI(n):
        x,y,z=sorted(xyz)
        yy.add(y)
        zxy[z].append((x,y))
    coy= {y: i+1 for i, y in enumerate(sorted(yy))}
    #print(zxy)

    dp=defaultdict(BitMax)
    ans=0
    for z,xy in sorted(zxy.items()):
        xyv=[]
        for x,y in xy:
            cy=coy[y]
            val=1
            for sx,bit in dp.items():
                if sx>=x:continue
                val=max(val,bit.max(cy-1)+1)
            ans=max(ans,val)
            xyv.append((x,cy,val))
        for x,cy,v in xyv:dp[x].update(cy,v)

    print(ans)

main()