class UnionFind:
    def __init__(self, n):
        self.parent = list(range(n)) #親ノード
        self.size = [1]*n #グループの要素数
 
    def root(self, x): #root(x): xの根ノードを返す．
        while self.parent[x] != x:
            self.parent[x] = self.parent[self.parent[x]]
            x = self.parent[x]
        return x 
 
    def merge(self, x, y): #merge(x,y): xのいる組とyのいる組をまとめる
        x, y = self.root(x), self.root(y)
        if x == y: return False
        if self.size[x] < self.size[y]: x,y=y,x #xの要素数が大きいように
        self.size[x] += self.size[y] #xの要素数を更新
        self.parent[y] = x #yをxにつなぐ
        return True
 
    def issame(self, x, y): #same(x,y): xとyが同じ組ならTrue
        return self.root(x) == self.root(y)
        
    def getsize(self,x): #size(x): xのいるグループの要素数を返す
        return self.size[self.root(x)]


n,m = map(int,input().split())
lr = [list(map(int,input().split())) for _ in range(n)]

UF = UnionFind(2*n)
ok = 1
for i in range(n):
    li,ri = lr[i]
    lli,rri = m-1-ri,m-1-li
    for j in range(i+1,n):
        lj,rj = lr[j]
        c = 0
        if li <= rj and lj <= ri:
            if not UF.merge(i,j): ok = 0
            if not UF.merge(i+n,j+n): ok = 0
        if lli <= rj and lj <= rri:
            if not UF.merge(i+n,j): ok = 0
            if not UF.merge(i,j+n): ok = 0

print("YES" if ok else "NO")