#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import array


def can_make_good_wall(pink_rows):
    return all(map(lambda x: x <= 2, pink_rows))


def main():
    n, m = map(int, input().split())
    pink_rows = array.array("I", (0 for _ in range(m)))
    for _ in range(n):
        l, r = map(int, input().split())
        for c in range(l, r + 1):
            pink_rows[c] += 1
            pink_rows[m - c - 1] += 1
    print("YES" if can_make_good_wall(pink_rows) else "NO")


if __name__ == '__main__':
    main()