#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ALL(v) v.begin(), v.end()
typedef long long ll;

#include <bits/stdc++.h>
using namespace std;

int main(){
  int n,m;
  cin>>n>>m;
  
  vector<ll> T(m+1);
  vector<ll> P(m+1);
  T[0]=0;
  P[0]=0;
  rep(i,m){
    cin>>T[i+1]>>P[i+1];
  }
  
  bool b=true;
  
  for(int i=0;i<m;i++){
    if(T[i+1]-T[i]<abs(P[i+1]-P[i])) b=false;
  }
  if(b) cout<<"Yes"<<endl;
  else cout<<"No"<<endl;

  return 0;
}