#include<bits/stdc++.h>

using namespace std;

using ll=long long;
const int N=100;
int n;
int w[N];
pair<int,int> a[N];
int ans[N],rest;
ll Ans;
void Dfs(int d)
{
    if(d==0)
    {
        if(rest) return;
        priority_queue<int> group,people;
        int p=0;
        for(int i=1;i<=n;i++)
        {
            for(int j=1;j<=ans[i]*i;j++)
                group.push(i);
            while(p+1<=n && a[p+1].first<=i)
            {
                people.push(a[p+1].second);
                p++;
            }
            while(group.size() && people.size())
            {
                if(people.top()>=group.top()) people.pop(),group.pop();
                else break;
            }
            while(group.size()) group.pop();
        }
        if(group.size()) return;
        if(people.size()) return;
        for(int i=1;i<=n;i++)
            cerr<<ans[i]<<" ";
        ll tmp=0;
        for(int i=1;i<=n;i++)
            tmp+=ans[i]*w[i];
        cerr<<"|"<<tmp<<"\n";
        Ans=max(Ans,tmp);
        // for(int i=1;i<=n;i++)
        //     cout<<ans[i]<<" ";
        // cout<<"\n";
        return;
    }
    Dfs(d-1);
    int tmp=rest;
    while(rest>=d)
    {
        ans[d]++;
        rest-=d;
        Dfs(d-1);
    }
    ans[d]=0;
    rest=tmp;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    cin>>n;
    for(int i=1;i<=n;i++)
        cin>>a[i].first>>a[i].second;
    sort(a+1,a+n+1);
    for(int i=1;i<=n;i++)
        cin>>w[i];
    rest=n;
    Ans=-1e18;
    Dfs(n);
    if(Ans==(ll)-1e18) cout<<"impossible\n";
    else cout<<Ans<<"\n";
    return 0;
}