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

int main() {
  int N, M;
  cin >> N >> M;
  vector<pair<int, long>> V(M);
  for (long i = 0, t, p; cin >> t >> p; i++) V.at(i) = {t, p};
  V.push_back({0, 0});
  sort(V.begin(), V.end());
  for (long i = 0; i + 1 < M + 1; i++) {
    auto [t1, p1] = V.at(i);
    auto [t2, p2] = V.at(i + 1);
    if (t2 - t1 < p2 - p1) return cout << "No" << "\n", 0;
  }
  cout << "Yes" << "\n";
}