#include <bits/stdc++.h>
using namespace std;
signed main() {
int n,m; cin>>n>>m;
vector<int>s(n);
for(auto &z : s)
cin>>z;
vector<int>w(m);
for(auto &z : w)
cin>>z;
int64_t ans = 0LL;
vector<int>place(m);
priority_queue<int>pq;
for(int i = 0 ; i < n ; i++) pq.push(-i);
queue<int>line;
for(int i = 0 ; i < 2*m ; i++) {
while(!line.empty()) {
if(pq.empty()) break;
place[line.front()] = -pq.top();
ans += (s[-pq.top()]) * (w[line.front()]);
pq.pop();
line.pop();
}
int x; cin>>x;
if(x > 0) {
x--;
line.push(x);
} else {
x = -x;
x--;
pq.push(-(place[x]));
}
}
cout << ans;
}
