# coding: utf-8

def readData():
    n = input()
    box_list = []
    while len(box_list) != n:
        box = map(int, raw_input().split())
        box.sort()
        box_list.append(box)
    box_list.sort()
    return n, box_list

# box2のほうが大きければTrueを返す
def compare_box(box1, box2):
    for t in xrange(3):
        if box2[t] <= box1[t]:
            return False
    return True

def matryoshka(n, box_list):
    dp = [1] * n
    for i in xrange(n-2, -1, -1):
        for j in xrange(i+1, n):
            if compare_box(box_list[i], box_list[j]):
                dp[i] = max(dp[i], dp[j]+1)
    print max(dp)
    
if __name__ == "__main__":
    n, box_list = readData()
    matryoshka(n, box_list)