#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N=1.5e4+5;
struct node{
	int bh,sm;
	friend bool operator<(node a,node b){
		return a.sm>b.sm;
	}
}g[N];
int n,m,w[N],he,qz[N],mk[N],rs[N];
vector<bitset<N> >f[N];
vector<int>jl[N];
priority_queue<pair<int,int> >q;
void solve(int i,int j,int k){
	if(i>n)return;
	if(j&&f[i][j-1][k]){
		solve(i,j-1,k);
		return;
	}
	solve(i+1,j,k+j);
	for(int i=1;i<=j;i++)rs[i]++;
}
signed main(){
	cin>>n;
	for(int i=1;i<=n;i++)cin>>g[i].sm,g[i].bh=i,he+=g[i].sm;
	cin>>m;
	for(int i=1;i<=m;i++)cin>>w[i],mk[w[i]]=1;
	sort(g+1,g+n+1);
	for(int i=1;i<=n;i++)qz[i]=qz[i-1]+g[i].sm;
	f[n+1].resize(he/(n+1)+1);f[n+1][0][he]=1;
	for(int i=n;i>=1;i--){
		f[i].resize(he/i+1);
		for(int j=0;j<=he/(i+1);j++){
			f[i][j]=f[i+1][j]>>j;
		}
		if(mk[i]){
			for(int j=1;j<=he/i;j++){
				f[i][j]|=f[i][j-1];
			}
		}
		for(int j=0;j<=he/i;j++){
			f[i][j]=f[i][j]>>qz[i]<<qz[i];
		}
	}
	for(int i=0;i<=he;i++){
		if(f[1][i][i]){
			cout<<i<<"\n";
			solve(1,i,i);
			for(int j=1;j<=i;j++)rs[j]++,q.push({rs[j],j});
			for(int j=1;j<=n;j++){
				vector<pair<int,int> >qs;
				for(int k=1;k<=g[j].sm;k++){
					auto x=q.top().second;
					q.pop();
					jl[x].push_back(g[j].bh);
					qs.push_back({rs[x]-jl[x].size(),x});
				}
				for(auto c:qs)q.push(c);
			}
			for(int j=1;j<=i;j++){
				cout<<rs[j]<<" ";
				for(auto c:jl[j])cout<<c<<" ";
				cout<<"\n";
			}
			return 0;
		}
	}
	cout<<-1;
}