#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 1000000000


int main(){
	
	int N,M;
	cin>>N>>M;
	
	vector<long long> T(M+1,0),P(M+1,0);
	
	for(int i=1;i<=M;i++)cin>>T[i]>>P[i];
	
	for(int i=1;i<=M;i++){
		if(abs(T[i]-T[i-1])<abs(P[i]-P[i-1])){
			cout<<"No"<<endl;
			return 0;
		}
	}
	
	cout<<"Yes"<<endl;
	
	return 0;
}