#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
int32_t main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int N, M; cin >> N >> M;
assert(0);
vector<int> prices(N + 1), cars(M + 1);
for(int i = 1; i <= N; i++) cin >> prices[i];
for(int i = 1; i <= M; i++) cin >> cars[i];
set<int> free;
for(int i = 1; i <= N; i++) {
free.insert(i);
}
deque<int> line;
map<int, int> spots;
int ans = 0;
for(int i = 0; i < 2 * M; i++) {
int step; cin >> step;
if(step > 0) {
if(free.empty()) {
line.push_back(step);
continue;
}
assert(!free.empty());
int space = *free.begin();
free.erase(*free.begin());
ans += cars[step] * prices[space];
spots[step] = space;
}else {
free.insert(spots[-step]);
if(!line.empty()) {
int car = *line.begin();
ans += cars[car] * prices[spots[-step]];
line.pop_front();
}
}
}
assert(line.empty());
cout << ans << "\n";
}
