//https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

//

use std::cmp::{max, min};

fn dfs(v: usize, g: &Vec<Vec<usize>>, used: &mut [bool], stack: &mut Vec<usize>) {
    assert!(!used[v]);
    used[v] = true;
    for &u in &g[v] {
        if !used[u] {
            dfs(u, g, used, stack);
        }
    }
    stack.push(v);
}

fn fill_dfs(k: u32, v: usize, g: &Vec<Vec<usize>>, dp: &mut [u32]) {
    assert!(dp[v] > k);
    dp[v] = k;
    for &u in &g[v] {
        if dp[u] > k {
            fill_dfs(k, u, g, dp);
        }
    }
}

fn run() {
    input! {
        n: usize,
        m: u32,
        p: [(u32, u32); n],
    }
    let mut g = vec![vec![]; 2 * n];
    for i in 0..n {
        let (a, b) = (p[i].0, p[i].1 + 1);
        let (ia, ib) = (m - b, m - a);
        for j in 0..i {
            let (c, d) = (p[j].0, p[j].1 + 1);
            let (ic, id) = (m - d, m - c);
            if max(a, c) < min(b, d) {
                g[i].push(j + n);
                g[j].push(i + n);
            }
            if max(a, ic) < min(b, id) {
                g[i].push(j);
                g[j + n].push(i + n);
            }
            if max(ia, c) < min(ib, d) {
                g[i + n].push(j + n);
                g[j].push(i);
            }
            if max(ia, ic) < min(ib, id) {
                g[i + n].push(j);
                g[j + n].push(i);
            }
        }
    }
    let mut ig = vec![vec![]; 2 * n];
    for s in 0..(2 * n) {
        for &t in &g[s] {
            ig[t].push(s);
        }
    }
    let mut used = vec![false; 2 * n];
    let mut q = vec![];
    for i in 0..(2 * n) {
        if used[i] {
            continue;
        }
        dfs(i, &g, &mut used, &mut q);
    }
    let mut id = vec![5000; 2 * n];
    let mut k = 0;
    for v in q {
        if id[v] < k {
            continue;
        }
        fill_dfs(k, v, &ig, &mut id);
        k += 1;
    }
    for i in 0..n {
        if id[i] == id[i + n] {
            println!("NO");
            return;
        }
    }
    println!("YES");
}

fn main() {
    run();
}