import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		sc.nextInt();
		int infoNum = sc.nextInt();
		int prevKey = 0;
		int prevValue = 0;
		int nextKey = 0;
		int nextValue = 0;
		for(int i = 0; i < infoNum; i++) {
			nextKey = sc.nextInt();
			nextValue = sc.nextInt();
			if(Math.abs(nextKey - prevKey) < Math.abs(nextValue - prevValue)) {
				System.out.println("No");
				return;
			}
			prevKey = nextKey;
			prevValue = nextValue;
		}
		System.out.println("Yes");
	}
}