#include <iostream>
#include <algorithm>
using namespace std;
int m,n;
struct node
{
int t;
int fa;
}w[514];
int main() {
cin>>m>>n;
for(int i = 1;i <= n;i++)
{
cin>>w[i].t;
}
for(int i = 1;i <= n;i++)
{
cin>>w[i].fa;
}
for(int i = 1;i <= n;i++)
{
bool flag;
for(int j = w[i].t;j >= 1;j--)
{
if(vis[j] == 0)
{
vis[j] = 1;
break;
}
}
if(flag == 0)
{
m -= w[i].fa;
}
}
cout<<m<<endl;
return 0;
}