#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>
using namespace std;
//dragons code forces
int n,x,i,s,y;
int main()
{

    vector<pair<int, int> >v;
    cin>>s>>n;
    for(i=0;i<n;i++)
      {
          cin>>x>>y;
        v.push_back({x,y});
      }
      sort(v.begin(),v.end());
      for(i=0;i<v.size();i++)
      {

        if (s<=v[i].first)
        {cout<<"NO\n";
        return 0;}
     s+=v[i].second;
        }
        cout<<"YES\n";
    return 0;
}