#[allow(unused_imports)] use std::cmp::{max, min}; #[allow(unused_imports)] use std::collections::{HashMap, HashSet, BTreeSet}; mod util { use std::io::stdin; use std::str::FromStr; use std::fmt::Debug; #[allow(dead_code)] pub fn line() -> String { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.trim().to_string() } #[allow(dead_code)] pub fn get() -> T where ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.trim().parse().unwrap() } #[allow(dead_code)] pub fn gets() -> Vec where ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); line.split_whitespace() .map(|t| t.parse().unwrap()) .collect() } #[allow(dead_code)] pub fn get2() -> (T, U) where ::Err: Debug, ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); let mut iter = line.split_whitespace(); ( iter.next().unwrap().parse().unwrap(), iter.next().unwrap().parse().unwrap(), ) } #[allow(dead_code)] pub fn get3() -> (S, T, U) where ::Err: Debug, ::Err: Debug, ::Err: Debug, { let mut line: String = String::new(); stdin().read_line(&mut line).unwrap(); let mut iter = line.split_whitespace(); ( iter.next().unwrap().parse().unwrap(), iter.next().unwrap().parse().unwrap(), iter.next().unwrap().parse().unwrap(), ) } } #[allow(unused_macros)] macro_rules! debug { ($x: expr) => { println!("{}: {:?}", stringify!($x), $x) } } fn main() { let n: usize = util::get(); let boxes: Vec> = (0..n) .map(|_| { let mut v = util::gets::(); v.sort(); v }) .collect::>() .iter() .cloned() .collect(); let mut dp = vec![1; n]; for i in 0..n { let b1 = &boxes[i]; for k in 0..i { let b2 = &boxes[k]; if b1[0] > b2[0] && b1[1] > b2[1] && b1[2] > b2[2] { dp[i] = max(dp[i], dp[k] + 1); } } } println!("{}", dp.iter().max().unwrap()); }