#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int n, m;
  cin >> n >> m;
  ll now = 0, pos = 0;
  bool ans = true;
  rep(_, m) {
    ll t, p;
    cin >> t >> p;
    if (t - now >= abs(pos - p)) {
      now = t;
      pos = p;
    }
    else {
      ans = false;
    }
  }
  cout << (ans ? "Yes" : "No") << endl;
  return 0;
}