import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,copy,functools
import time,random

sys.setrecursionlimit(10**7)
inf = 10**20
eps = 1.0 / 10**10
mod = 10**9+7
mod2 = 998244353
dd = [(-1,0),(0,1),(1,0),(0,-1)]
ddn = [(-1,0),(-1,1),(0,1),(1,1),(1,0),(1,-1),(0,-1),(-1,-1)]

def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(): return [list(map(int, l.split())) for l in sys.stdin.readlines()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def S(): return input()
def pf(s): return print(s, flush=True)
def pe(s): return print(str(s), file=sys.stderr)
def JA(a, sep): return sep.join(map(str, a))
def JAA(a, s, t): return s.join(t.join(map(str, b)) for b in a)

def scc(n, e, re):
    v = [None] * n
    t = []
    def dfs(i):
        v[i] = 0
        for b in e[i]:
            if v[b] is None:
                dfs(b)
        t.append(i)

    for i in range(n):
        if v[i] is None:
            dfs(i)

    r = [None] * n
    def dfs2(i, p):
        r[i] = p
        for b in re[i]:
            if r[b] is None:
                dfs2(b, p)

    for c in t[::-1]:
        if r[c] is None:
            dfs2(c, c)

    return r

def main():
    n,m = LI()
    lr = [LI() for _ in range(n)]

    e = [[] for _ in range(n*2)]
    re = [[] for _ in range(n*2)]
    def f(i,ni,li,ri,j,nj,lj,rj):
        if li<=lj<=ri or li<=rj<=ri or lj<=li<=rj:
            e[i].append(nj)
            re[nj].append(i)
            e[j].append(ni)
            re[ni].append(j)
            return 1
        return 0

    for i in range(n):
        li,ri = lr[i]
        rli,rri = m-ri-1,m-li-1
        for j in range(i+1,n):
            lj,rj = lr[j]
            rlj,rrj = m-rj-1,m-lj-1
            ac = 0
            ac += f(i,i+n,li,ri,j,j+n,lj,rj)
            ac += f(i,i+n,li,ri,j+n,j,rlj,rrj)
            ac += f(i+n,i,rli,rri,j,j+n,lj,rj)
            ac += f(i+n,i,rli,rri,j+n,j,rlj,rrj)
            if ac > 3:
                return "NO"

    r = scc(n*2,e,re)
    for i in range(n):
        if r[i] == r[i+n]:
            return "NO"

    return "YES"

# start = time.time()
print(main())
# pe(time.time() - start)