#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  ll n, m;
  cin >> n >> m;
  ll pos = 0, time = 0;
  while (m--) {
    ll t, p;
    cin >> t >> p;
    ll dx = abs(p - pos);
    ll dt = t - time;
    if (dx <= dt) {
      pos = p;
      time = t;
    } else {
      cout << "No" << '\n';
      return 0;
    }
  }
  cout << "Yes" << '\n';
}