#include<bits/stdc++.h>
using namespace std;
#define int long long
#define PII pair<int,int>
#define lson 2*p
#define rson 2*p+1
#define x first
#define y second
// #define endl "\n"
const int N=2e5+10;
const int mod=1e9+7;
vector<int> v;
int ans=-1e18;
int w[N];
PII p[N];
bool cmp(PII a,PII b) {
	return a.y<b.y;
}
int n;
void dfs(int now,int last) {
	if(now==n) {
		priority_queue<PII,vector<PII>,greater<PII> > q;
		int pos=0;
		// for(int x:v) cout<<x<<" ";
		// cout<<endl;
		for(int x:v) {
			while(pos+1<=n&&p[pos+1].y>=x) pos++,q.push({p[pos].x,pos});
			if(q.size()<x) return ;
			for(int i=1;i<=x;i++) {
				auto [y,z]=q.top();
				q.pop();
				if(y>x) return ;
			}
		}
		int val=0;
		for(int x:v) val+=w[x];	
		ans=max(ans,val);
		return ;
	}
	for(int i=last;i<=n-now;i++) {
		v.push_back(i);
		dfs(now+i,i);
		v.pop_back();
	}
}
void solve() {
	cin>>n;
	for(int i=1;i<=n;i++) cin>>p[i].x>>p[i].y;
	for(int i=1;i<=n;i++) cin>>w[i];
	sort(p+1,p+n+1,cmp);
	double st=clock();
	dfs(0,1);
	double ed=clock();
	if(ans==-1e18) {
		cout<<"impossible"<<endl;
		return ;
	}
	cout<<ans<<endl;
	// cout<<ed-st<<endl;
} 
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int T=1;
	// cin>>T;
	while(T--) {
		solve();
	}
}