#include <bits/stdc++.h>
using namespace std;
int main(){
  int N, M;
  cin >> N >> M;
  vector<long long> T(M + 1);
  vector<int> P(M + 1);
  T[0] = 0;
  P[0] = 0;
  for (int i = 1; i <= M; i++){
    cin >> T[i] >> P[i];
  }
  bool ok = true;
  for (int i = 0; i < M; i++){
    if (abs(T[i + 1] - T[i]) < abs(P[i + 1] - P[i])){
      ok = false;
    }
  }
  if (!ok){
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
}