#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


# %%
import numpy as np
N = int(readline())
XYZ = np.array(read().split(), np.int32).reshape(N, 3)
XYZ.sort(axis=1)


# %%
X, Y, Z = XYZ.T
ind = np.argsort(X)
X = X[ind]
Y = Y[ind]
Z = Z[ind]


# %%
dp = np.zeros(N, np.int32)
for n in range(N):
    x = X[n]
    y = Y[n]
    z = Z[n]
    smaller = (X < x) & (Y < y) & (Z < z)
    dp[n] = (dp * smaller).max() + 1


# %%
print(dp.max())