N = int(input())
XYZ = []
for i in range(N):
    xyz = list(map(int,input().split()))
    xyz.sort()
    XYZ.append(xyz)
E = [[] for _ in range(N)]
D = [0] * N
for i in range(N-1):
    x1,y1,z1 = XYZ[i]
    for j in range(i+1,N):
        x2,y2,z2 = XYZ[j]
        if x1 > x2 and y1 > y2 and z1 > z2:
            E[j].append(i)
            D[i] += 1
        if x1 < x2 and y1 < y2 and z1 < z2:
            E[i].append(j)
            D[j] += 1
Q = []
for i in range(N):
    if D[i] == 0:
        Q.append(i)
dp = [1] * N
Q2 = []
while Q:
    while Q:
        x = Q.pop()
        for y in E[x]:
            dp[y] = max(dp[y],dp[x]+1)
            D[y] -= 1
            if D[y] == 0:
                Q2.append(y)
    Q,Q2 = Q2,Q
print(max(dp))