#include<bits/stdc++.h>

using namespace std;
using ll=long long;
#define rep2(i, a, n) for(int i = (a); i < (n); i++)
#define rep(i, n) rep2(i,0,n)

void in(){} template<typename Head,typename... Tail> void in(Head&& head,Tail&&... tail){cin>>head;in(forward<Tail>(tail)...);}

void flagfunc3(bool flag){cout<<(flag?"Yes\n":"No\n");}

int main(){
  cin.tie(nullptr);ios_base::sync_with_stdio(false);
  ll n,m;
  in(n,m);
  ll t[m],p[m];
  rep(i,m)cin>>t[i]>>p[i];

  if(m==1){
    flagfunc3(true);
  }else{
  bool flag=true;
  rep(i,m-1){
    if(t[i+1]-t[i]<abs(p[i+1]-p[i])){
      flag=false;
      break;
    }
  }
  flagfunc3(flag);
  }
}