#include <bits/stdc++.h>
using namespace std;
int main () {
int n, m; cin >> n >> m;
vector<int> a(n);
for (int i = 0; i < n; i++) {
cin >> a[i];
}
vector<int> b(m);
for (int i =0 ; i < m; i++) {
cin >> b[i];
}
queue<int> q;
vector<int> departures(m);
vector<bool> used(m, false);
int ans = 0;
for (int i = 0; i < 2*m; i++) {
int num; cin >> num;
if (num > 0) {
q.push(num-1);
}
else {
used[departures[abs(num)-1]] = false;
}
for (int j = 0; j < n; j++) {
if (!used[j]) {
if (q.size()) {
used[j] = true;
ans += a[j] * b[q.front()];
departures[q.front()] = j;
q.pop();
}
}
}
}
cout << ans << '\n';
}
