#include <bits/stdc++.h>
#define ll long long
#define pi 3.14159265358979
#define mod 1000000007
#define rep(i,n) for(ll i=0;i<n;i++)
using namespace std;

int main(){
    ll n,m,t=0,p=0,tt,pp,ans=0;
    cin>>n>>m;
    rep(i,m){
        tt=t;
        pp=p;
        cin>>t>>p;
        if(t-tt<abs(p-pp)){
            ans=1;
            break;
        }
    }
    if(ans==0){
        cout<<"Yes";
    }else{
        cout<<"No";
    }
}