#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i, n) for(int i=0; i<n; i++)
#define REPR(i, n) for(int i=n-1; i>=0; i--)
#define FOR(i, m, n) for(int i=m; i<n; i++)
#define ALL(v) v.begin(), v.end()
#define SIZE(x) ll(x.size()) 
using P = pair<int, int>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = 2e9;
const ll LINF = (1LL<<60);

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n,m;
  cin >> n >> m;
  vector<ll> t(m+1), p(m+1);
  REP(i,m) cin >> t[i+1] >> p[i+1];
  
  REP(i,m){
    ll tsub = t[i+1] - t[i];
    ll psub = abs(p[i+1] - p[i]);
    if(tsub<psub){
      cout << "No\n";
      return 0;
    }
  }
  
  cout << "Yes\n";
  return 0;
}