import java.util.*;
import java.io.*;
import java.awt.geom.*;
import java.math.*;

public class No0274 {

	static final Scanner in = new Scanner(System.in);
	static final PrintWriter out = new PrintWriter(System.out,false);

	static void solve() {
		int n = in.nextInt();
		int m = in.nextInt();
		boolean[] f = new boolean[m];
		for (int i=0; i<n; i++) {
			int l = in.nextInt();
			int r = in.nextInt();
			if (l > m-r-1) {
				int t = l;
				l = m - r - 1; r = m - t - 1;
			}

			// trace(f);

			boolean flag = true;
			for (int j=l; j<=r; j++) {
				if (f[j]) {
					flag = false;
					break;
				}
			}

			if (flag) {
				for (int j=l; j<=r; j++) {
					f[j] = true;
				}
			} else {
				int t = l;
				l = m - r - 1; r = m - t - 1;
				boolean flag2 = true;
				for (int j=l; j<=r; j++) {
					if (f[j]) {
						flag2 = false;
						break;
					}
				}

				if (flag2) {
					for (int j=l; j<=r; j++) {
						f[j] = true;
					}
				} else {
					out.println("NO");
					return;
				}
			}
		}

		out.println("YES");
	}

	public static void main(String[] args) {
		long start = System.currentTimeMillis();

		solve();
		out.flush();

		long end = System.currentTimeMillis();
		//trace(end-start + "ms");
		in.close();
		out.close();
	}

	static void trace(Object... o) { System.out.println(Arrays.deepToString(o));}
}