#include<bits/stdc++.h>
using namespace std;
#define int long long
int32_t main()
{
cin.tie(0);
cout.tie(0);
ios::sync_with_stdio(false);
int t=1;
//cin>>t;
while(t--)
{
int n,k,x,y;
cin>>k>>n;
vector<pair<int,int>>v;
for(int i=0;i<n;i++)
{
cin>>x>>y;
v.push_back({x,y});
}
sort(v.begin(),v.end());
for(int i=0;i<n;i++)
{
if(k>v[i].first)
{
k+=v[i].second;
}
else
{
cout<<"NO";
return 0;
}
}
cout<<"YES";
}
return 0;
}
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