RT,求调

#include<bits/stdc++.h>
using namespace std;
struct node{int x,y;}a[50000];
int cmp(node a1,node b1)
{
   if(a1.y<=b1.y)
   	return a1.y<b1.y;
   return a1.y>b1.y;
}
int main()
{
   int n,s;scanf("%d%d",&n,&s);int num,ans;scanf("%d%d",&num,&ans); 
   int m=num+ans;
   int x=0 ;
   for(int i=1;i<=n;i++)
   	scanf("%d%d",&a[i].x,&a[i].y);
   sort(a+1,a+1+n,cmp);
   for(int i=1;i<=n;i++)
   {
   	if(a[i].x>m||m==0)
   		break;
   	if(a[i].y<=s&&a[i].x<=m)
   	{
   		s-=a[i].y;
   		x++;
   	}
   }
   	
   printf("%d",x);
   return 0;
}