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


def solve(n, m, lr):
    used = [False] * m
    lr.sort(key=lambda lri: lri[1] + 1 - lri[0], reverse=True)
    for i in range(n):
        ok = True
        for j in range(m):
            if lr[i][0] <= j <= lr[i][1] and used[j]:
                ok = False

        if ok:
            for j in range(m):
                if lr[i][0] <= j <= lr[i][1]:
                    used[j] = True
            continue

        ok = True
        for j in range(m):
            if m - 1 - lr[i][1] <= j <= m - 1 - lr[i][0] and used[j]:
                ok = False

        if ok:
            for j in range(m):
                if m - 1 - lr[i][1] <= j <= m - 1 - lr[i][0]:
                    used[j] = True

            continue

        return 0

    return 1


print("YES" if solve(n, m, lr) else "NO")