#include <bits/stdc++.h>
using namespace std;
template <typename T> bool chmax(T &u, const T z) { if (u < z) {u = z; return true;} else return false; }
template <typename T> bool chmin(T &u, const T z) { if (u > z) {u = z; return true;} else return false; }
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ll long long 
typedef pair<ll, ll> P;
//const int MAX=10100;
const ll INF=1LL<<60;

int main(){
  int n,m;
  cin>>n>>m;
  vector<int>t(n),p(n);
  rep(i,m)cin>>t[i]>>p[i];
  rep(i,m){
    if(t[i]<p[i]){
      cout<<"No"<<endl;
      return 0;
    }
  }
  int jikan=0;
  int kusuri=0;
  for(int i=1;i<m-1;i++){
    jikan=t[i]-t[i-1];
    kusuri=abs(p[i]-p[i-1]);
    if(jikan<kusuri){
      cout<<"No"<<endl;
      return 0;
    }


  }
  cout<<"Yes"<<endl;
  return 0;
}