import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
//		int n = Integer.parseInt(sa[0]);
		int m = Integer.parseInt(sa[1]);
		long[] t = new long[m];
		int[] p = new int[m];
		for (int i = 0; i < m; i++) {
			sa = br.readLine().split(" ");
			t[i] = Long.parseLong(sa[0]);
			p[i] = Integer.parseInt(sa[1]);
		}
		br.close();

		long nt = 0;
		long np = 0;
		for (int i = 0; i < m; i++) {
			if (t[i] - nt < Math.abs(p[i] - np)) {
				System.out.println("No");
				return;
			}
			nt = t[i];
			np = p[i];
		}
		System.out.println("Yes");
	}
}