import sys
readline = sys.stdin.readline

def crossing(M, b0, b1):
    l0, r0 = b0
    l1, r1 = b1
    t0 = l1 <= r0 and l0 <= r1
    l0, r0 = M - 1 - r0, M - 1 - l0
    t1 = l1 <= r0 and l0 <= r1
    if t0 and t1:
        return "NG"
    if t0 or t1:
        return True
    return False

def dfs(x, G, color, now):
    color[x] = now
    for y in G[x]:
        if color[y] >= 0:
            if color[y] == now:
                return False
            continue
        if not dfs(y, G, color, 1 - now):
            return False
    return True

def main():
    N, M = map(int, readline().split())
    blocks = [tuple(map(int, readline().split())) for _ in range(N)]
    G = [[] for _ in range(N)]
    for i in range(N):
        for j in range(i + 1, N):
            t = crossing(M, blocks[i], blocks[j])
            if t == "NG":
                print("NG")
                return
            if t:
                G[i].append(j)
                G[j].append(i)

    is_bipartite = True
    color = [-1] * N
    for x in range(N):
        if color[x] >= 0:
            continue
        if not dfs(x, G, color, 0):
            is_bipartite = False
    print("YES" if is_bipartite else "NO")

if __name__ == "__main__":
    main()