#include <iostream>
#include <vector>
#include <algorithm>
 
using namespace std;
struct E{
	int a,b;
	bool operator<(const E& e1)const{
		if(a!=e1.a)return a<e1.a;
		return b<e1.b;
	}
};
vector<E> vs;
 
int f(int n1,int m1,int k1,int sum1){
	if(n1==0 || m1==0 || k1==0){
		return sum1+m1;
	}
	int res1=0;
	int res2=0;
	if(n1>0 && k1>0){
		int d1=min(vs[n1].b,m1);
		res1=f(n1-1,m1-d1,k1-1,sum1+d1*vs[n1].a);
	}
	res2=f(n1-1,m1,k1,sum1);
	return max(res1,res2);
}
 
int main() {
	int n,m,k;
	cin>>n>>m>>k;
	vector<int> vsa;
 
	for(int i=0;i<n;i++){
		int x;
		cin>>x;
		vsa.push_back(x);
	}
	E e;
	vs.push_back(e);
	for(int i=0;i<n;i++){
		E e1;
		e1.a=vsa[i];
		cin>>e1.b;
		vs.push_back(e1);
	}
	sort(vs.begin(),vs.end());
	cout<<f(n,m,k,0)<<endl;
	return 0;
}

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

MTEgNjEwNCAzCjYyMCA4MDYgODgxIDg1OCA1NTkgNTUzIDUwMiA1NTQgOTYyIDMyNSA0MzUKOTI3OSA0NjQgNzMyNyAyNTQ5IDk4MzIgNjU5NSA4MjAwIDg3MjAgNzY1OCA2MzkgOTk5Mgo=

11 6104 3
620 806 881 858 559 553 502 554 962 325 435
9279 464 7327 2549 9832 6595 8200 8720 7658 639 9992