#include<bits/stdc++.h>
#define rep(i, x) for(ll i = 0; i < x; i++)
#define rep2(i, x) for(ll i = 1; i <= x; i++)
#define all(a) (a).begin(),(a).end()
using ll = long long;
using ld = long double;
using namespace std;

signed main() {
	ll n, m, cnt1 = 0, cnt2 = 0; cin >> n >> m;
	rep(i, m) {
		ll t, p; cin >> t >> p;
		if (t - cnt1 < abs(p - cnt2)) { cout << "No\n"; return 0; }
		cnt1 = t; cnt2 = p;
	}
	cout << "Yes\n";
	return 0;
}