N, M = map(int, input().split())
LR = [tuple(map(int, input().split())) for _ in range(N)]
locked = [False]*N

for i in range(M):
    flag = False
    
    for j in range(N):
        Lj, Rj = LR[j]
        
        if Lj<=i<=Rj:
            if not flag:
                flag = True
            else:
                if locked[j]:
                    print('NO')
                    exit()
                else:
                    Lj, Rj = M-1-Rj, M-1-Lj
                    
                    if Lj<=i<=Rj:
                        print('NO')
                        exit()
                    
                    LR[j] = (Lj, Rj)
                    locked[j] = True

for i in range(N):
    flag = False
    
    for j in range(N):
        Lj, Rj = LR[j]
        
        if Lj<=i<=Rj:
            if not flag:
                flag = True
            else:
                print('NO')
                exit()
                
print('YES')