class SCC():
  def __init__(self,n):
    self.n=n
    self.e=[[] for i in range(self.n)]
    self.re=[[] for i in range(self.n)]
    return
  
  def add_edge(self,s,t):
    self.e[s]+=[t]
    self.re[t]+=[s]
    return
  
  def scc(self):
    v=[0]*self.n
    g=[0]*self.n
    o=[]
    for i in range(self.n):
      if v[i]==0:
        q=[i]
        while len(q)>0:
          s=q[-1]
          v[s]=1
          while g[s]<len(self.e[s]):
            t=self.e[s][g[s]]
            if v[t]==0:
              break
            g[s]+=1
          if g[s]<len(self.e[s]):
            q+=[t]
          else:
            o+=[s]
            q.pop()
    c=[-1]*self.n
    p=0
    for i in o[::-1]:
      if c[i]==-1:
        s=i
        c[s]=p
        q=[s]
        for s in q:
          for t in self.re[s]:
            if c[t]==-1:
              c[t]=p
              q+=[t]
        p+=1
    E=[[] for i in range(p)]
    for s in range(self.n):
      for t in self.e[s]:
        if c[s]!=c[t]:
          E[c[s]]+=[c[t]]
    d=[0]*p
    for s in range(p):
      for t in E[s]:
        d[t]+=1
    ts=[]
    q=[i for i in range(p) if d[i]==0]
    for s in q:
      ts+=[s]
      for t in E[s]:
        d[t]-=1
        if d[t]==0:
          q+=[t]
    d=[0]*p
    for i in range(p):
      d[ts[i]]=i
    l=[[] for i in range(p)]
    for i in range(self.n):
      l[d[c[i]]]+=[i]
    return l


class TwoSAT():
  def __init__(self,n):
    self.n=n
    self.g=SCC(self.n*2)
    return
  
  def add_clause(self,i,fi,j,fj):
    self.g.add_edge(i+self.n*(fi^1),j+self.n*(fj^0))
    self.g.add_edge(j+self.n*(fj^1),i+self.n*(fi^0))
    return
  
  def satisfiable(self):
    l=self.g.scc()
    self.c=[0]*n*2
    for i in range(len(l)):
      for j in l[i]:
        self.c[j]=i
    return all(self.c[i]!=self.c[i+self.n] for i in range(self.n))
  
  def answer(self):
    return [int(self.c[i]<self.c[i+self.n]) for i in range(self.n)]


n,m=map(int,input().split())
w=[tuple(map(int,input().split())) for i in range(n)]
g=TwoSAT(n)
for i in range(n-1):
  for j in range(i+1,n):
    for fi in range(2):
      for fj in range(2):
        li,ri=w[i]
        if fi:
          li,ri=m-1-ri,m-1-li
        lj,rj=w[j]
        if fj:
          lj,rj=m-1-rj,m-1-lj
        if min(ri,rj)-max(li,lj)+1>0:
          g.add_clause(i,fi^1,j,fj^1)
print(["NO","YES"][g.satisfiable()])