package main

import . "fmt"
import . "os"
import bf "bufio"

func main() {
	rd:=bf.NewReader(Stdin)
	var n,m int64
	Fscan(rd,&n,&m)
	var x int64
	for ;m>0;m-- {
		var t,p int64
		Fscan(rd,&t,&p)
		d:=p-x
		if d<0 {
			d=-d
		}
		if d>t {
			Println("No")
			return
		}
		x=p
	}
	Println("Yes")
	
}