#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
#define popcountll __builtin_popcountll
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
	int n, m; cin>>n>>m;
	ll t[100010], p[100010];
	t[0]=0, p[0]=0;
	for(int i=1; i<=m; i++) cin>>t[i]>>p[i];
	for(int i=0; i<m; i++){
		if(abs(p[i]-p[i+1])>t[i+1]-t[i]){
			cout<<"No"<<endl;
			return 0;
		}
	}
	cout<<"Yes"<<endl;
	return 0;
}