#include <iostream>
#include <bits/stdc++.h>
using namespace std;
int main() {
int n,s,temp1,temp2;
bool b=true;
cin>>s>>n;
int arr1[n] ;
int arr2[n] ;
for (int i=0;i<n;i++)
{
cin>>arr1[i]>>arr2[i];
}
for (int i = 1; i < n; i++)
{
for (int j = 0; j < n-1; j++)
{
if (arr1[j] == arr1[j+1]&&arr2[j]<arr2[j+1])
{
temp2 = arr2[j];
arr2[j] = arr2[j+1];
arr2[j+1] = temp2;
}
else if (arr1[j] > arr1[j+1])
{
temp1 = arr1[j];
arr1[j] = arr1[j+1];
arr1[j+1] = temp1;
temp2 = arr2[j];
arr2[j] = arr2[j+1];
arr2[j+1] = temp2;
}
}
}
for (int i=0;i<n;i++)
{
if(s>arr1[i])s=s+arr2[i];
else
{
b=false;
break;
}
}
if(b==true)cout<<"YES"<<endl;
else cout<<"NO"<<endl;
return 0;
}
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