#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef long double ld;
typedef pair<int,int> P;

int main() {
  int n, m;
  cin >> n >> m;
  int ok = 1;
  ll cur_p = 0, cur_t = 0;
  for (int i = 0; i < m; i++) {
    ll t, p;
    cin >> t >> p;
    if (abs(cur_t - t) >= abs(cur_p - p)) {
      cur_t = t;
      cur_p = p;
    } else ok = 0;
  }
  if (ok) cout << "Yes" << endl;
  else cout << "No" << endl;
  return 0;
}