// No.1205 Eye Drops
package main

import "fmt"

func main() {
	var n, m int
	fmt.Scan(&n, &m)
	type C struct {
		T int // time
		P int // position
	}
	ans := "Yes"
	mm := make([]C, m)
	for i := 0; i < m; i++ {
		fmt.Scan(&mm[i].T, &mm[i].P)
		if mm[i].T < mm[i].P {
			ans = "No"
		}
	}
	fmt.Println(ans)

}