#include <iostream>
#include <cassert>
#include <map>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  long N, M; cin >> N >> M;
  long pp = 0, pt = 0;
  bool ok = true;
  for (int i = 0; i < M; i++) {
    long T, P; cin >> T >> P;
    long dt = T - pt;
    long dp = abs(P - pp);
    ok &= dt >= dp;
    pt = T;
    pp = P;
  }
  cout << (ok? "Yes": "No") << endl;
  return 0;
}