n = gets.to_i
xyz = (1..n).map { gets.split.map(&:to_i).sort }.sort.reverse

dp = [1] * n
(1...n).each { |i|
	dp[i] = ((0...i).select { |j|
		(0...3).all? { |k| xyz[i][k] < xyz[j][k] }
	}.map { |i| dp[i] }.max || 0) + 1
}
puts dp.max