#include <bits/extc++.h>

#ifndef DUMP
#define DUMP(...) void(0)
#endif

using namespace std;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n, m;
  cin >> n >> m;
  int64_t x = 0, cur = 0;
  while (m--) {
    int64_t t, p;
    cin >> t >> p;
    if (abs(p - x) > abs(t - cur)) {
      cout << "No\n";
      exit(0);
    }
    x = p;
    cur = t;
  }
  cout << "Yes\n";
}