#include<bits/stdc++.h>
using namespace std;
using Int=long long;
using Real=long double;
template<class T,class S>inline bool chmin(T&A,S B){return(A>B?A=B,1:0);}
template<class T,class S>inline bool chmax(T&A,S B){return(A<B?A=B,1:0);}
#define REP(i,n)for(int i=0;i<(n);++i)
#define REP1(i,n)for(int i=1;i<=(n);++i)
#define ALL(x)begin(x),end(x)
#define drop(x){cout<<(x)<<'\n';return;}
Int N,M,T,P,pT,pP;
void sol()
{
	cin>>N>>M;
	REP(i,M)
	{
		cin>>T>>P;
		if(abs(T-pT)<abs(P-pP))drop("No");
		pT=T,pP=P;
	}
	cout<<"Yes\n";
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	cout<<fixed<<setprecision(16);
	int T=1;
	//cin>>T;
	while(T--)sol();
}