N = int(input())
Boxes = []
for _ in range(N):
    Boxes.append(sorted(list(map(int, input().split()))))
Boxes.sort()

dp = [1] * N
for i in range(N):
    for j in range(i):
        if all(Boxes[i][x] > Boxes[j][x] for x in range(3)):
            dp[i] = max(dp[i], dp[j] + 1)
print(dp[-1])