#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:x) cout << it << " "; cout << #y << endl;
typedef pair<int,int>pii;
typedef pair<pii,pii>pi2;
void solve(){
int n,m;
cin >> n >> m;
int rate[n+1];
for(int x=1;x<=n;x++){
cin >> rate[x];
}
int weight[m+1];
for(int x=1;x<=m;x++){
cin >> weight[x];
}
int index[m+1];
int temp;
set<int>se;
for(int x=1;x<=n;x++) se.insert(x);
int counter=0;
queue<int>q;
for(int x=0;x<2*m;x++){
cin >> temp;
if(temp>0){
q.push(temp);
}
else{
temp=-temp;
se.insert(index[temp]);
}
if(!se.empty()&&!q.empty()){
int hold=*se.begin();
se.erase(se.find(hold));
int hold2=q.front();
q.pop();
index[hold2]=hold;
counter+= rate[hold]*weight[hold2];
}
}
cout << counter;
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
//freopen("in.txt", "r", stdin);
int t=1;
//cin >> t;
while(t--){
solve();
}
}
