//程序思路：
//先对火元素排序(priority_queue)
//直接用次数运算

#include<bits/stdc++.h>
using namespace std;
long long n,m,k,s;
long long ans;
priority_queue<int,vector<int>,less<int> > q;
int main() 
{
	cin>>n>>m>>k;
	for(int i=1;i<=n;++i)
	{
		cin>>s;
		q.push(s);
		ans+=s;
	}
	for(int i=1;i<=m;++i)
	{
		cin>>s;
		ans+=s;
	}
	//cout<<"基础伤害"<<ans<<endl;
	int t=q.top(); 
	while(t>k&&q.size()&&n)
	{
		//cout<<"元素伤害加成"<<t<<endl;
		ans+=t;
		q.pop();
		t=q.top();
		n--;
		m--;
	}
	ans+=k*min(m,n);
	cout<<ans<<endl;
	return 0;
}