#include <bits/stdc++.h>
using namespace std;
int n, m, r[110], w[2010], pos[2010], id[110];
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m;
for (int i=1; i<=n; ++i) cin >> r[i];
for (int i=1; i<=m; ++i) cin >> w[i];
int ans=0;
queue<int> q;
for (int i=1; i<=m*2; ++i){
int x; cin >> x;
if (x>0){
q.push(x);
}else{
x=-x;
id[pos[x]]=0;
pos[x]=0;
}
while (q.size()){
int j=-1;
for (int k=1; k<=n; ++k) if (id[k]==0){
j=k;
break;
}
if (j==-1) break;
id[j]=q.front();
pos[q.front()]=j;
ans+=r[j]*w[q.front()];
q.pop();
}
}
cout << ans << '\n';
return 0;
}
