#include<iostream>
#include<string>
#include<iomanip>
#include<algorithm>
#include<deque>
#include<queue>
#include<cmath>
#include<vector>
#include<math.h>
#include<set>
#include<map>
using namespace std;
void mansour()
{
	std::ios_base::sync_with_stdio(0);
	cin.tie(NULL);
	cout.tie(NULL);
}
map<int,int>mp;
int main()
{
	mansour();
	/*The First*/
	long long n,s,a,b,m=0,c=0;
	cin>>s>>n;
	for(int i=0;i<n;i++)
	{
		cin>>a>>b;
		mp[a]+=b;
		m=max(m,a);
	}
	for(int i=0;i<10001;i++)
	{
	    if(s>i)
		{
		    //c++;
		    s+=mp[i];
		}
	}
	//cout <<c<<" "<<s<<" "<<m<<"\n";
	if(s>m)
		cout <<"YES\n";
	else
		cout <<"NO\n";
}

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