#https://tjkendev.github.io/procon-library/python/graph/2-sat.html
from collections import deque

def scc(N, G, RG):
    order = []
    used = [0]*N
    def dfs(s):
        used[s] = 1
        for t in G[s]:
            if not used[t]:
                dfs(t)
        order.append(s)
    for i in range(N):
        if not used[i]:
            dfs(i)
    group = [-1]*N
    label = 0
    order.reverse()
    for s in order:
        if group[s] != -1:
            continue
        que = deque([s])
        group[s] = label
        while que:
            v = que.popleft()
            for w in RG[v]:
                if group[w] != -1:
                    continue
                que.append(w)
                group[w] = label
        label += 1
    return group # topological ordering

N,M = map(int, input().split())
G = [[] for i in range(2*M)]
RG = [[] for i in range(2*M)]
# add (a ∨ b)
# a =  x_i if neg_i = 0
# a = ~x_i if neg_i = 1
def add_edge(i, neg_i, j, neg_j):
    #print(i,neg_i,j,neg_j)
    if neg_i:
        i0 = i+M; i1 = i
    else:
        i0 = i; i1 = i+M
    if neg_j:
        j0 = j+M; j1 = j
    else:
        j0 = j; j1 = j+M
    # add (~a ⇒ b)
    G[i1].append(j0); RG[j0].append(i1)
    # add (~b ⇒ a)
    G[j1].append(i0); RG[i0].append(j1)

# check if the formula is satisfiable
def check(group):
    for i in range(N):
        if group[i] == group[i+N]:
            return False
    return True

# assign values to variables
def assign(group):
    res = [0]*N
    for i in range(N):
        if group[i] > group[i+N]:
            res[i] = 1
    return res

l = [tuple(map(int, input().split())) for i in range(N)]
for i in range(N):
    L1,R1 = l[i]
    r_R1,r_L1 = M-L1-1,M-R1-1
    for j in range(i+1,N):
        L2,R2 = l[j]
        r_R2,r_L2 = M-L2-1,M-R2-1
        #print(L1,R1,r_L1,r_R1,L2,R2,r_L2,r_R2)
        if L1<=L2<=R1 or L1<=R2<=R1:
            add_edge(i,0,j,1)
            add_edge(j,0,i,1)

        if r_L1<=L2<=r_R1 or r_L1<=R2<=r_R1:
            add_edge(i,1,j,1)
            add_edge(j,0,i,0)

        if L1<=r_L2<=R1 or L1<=r_R2<=R1:
            add_edge(i,0,j,0)
            add_edge(j,1,i,1)

        if r_L1<=r_L2<=r_R1 or r_L1<=r_R2<=r_R1:
            add_edge(i,1,j,0)
            add_edge(j,1,i,0)
group = scc(2*M, G, RG)
if check(group):
    print("YES")
else:
    print("NO")