#include <bits/stdc++.h>
template<class T> inline bool chmin(T&a, T b){if(a > b){a = b; return true;}else{return false;}}
template<class T> inline bool chmax(T&a, T b){if(a < b){a = b; return true;}else{return false;}}
#define ll long long
#define double long double
#define rep(i,n) for(int i=0;i<(n);i++)
#define REP(i,n) for(int i=1;i<=(n);i++)
#define mod (ll)(1e9+7)
#define inf (ll)(3e18+7)
#define pi (double) acos(-1.0)
#define P pair<int,int>
#define PiP pair<ll,pair<ll,ll>>
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
using namespace std;

int main(){
	ll n, m;
	cin >> n >> m;
	vector<ll> t(m), p(m);
	rep(i, m)cin >> t[i] >> p[i];
	bool ans = true;
	t.insert(t.begin(), 0);
	p.insert(p.begin(), 0);
	REP(i, m){
		if(abs(p[i]-p[i-1]) > t[i]-t[i-1])ans = false;
	}
	cout << (ans ? "Yes" : "No") << endl;
}