n, m = map(int, input().split())
LR = []
for _ in range(n):
    l, r = map(int, input().split())
    r += 1
    l, r = min((l, r), (m - r, m - l))
    LR.append((l, r))
used = [False for _ in range(m)]
for l, r in sorted(LR):
    if any(used[i] for i in range(l, r)):
        l, r = m - r, m - l
    if any(used[i] for i in range(l, r)):
        print("NO")
        exit()
    for i in range(l, r):
        used[i] = True
print("YES")