#include<bits/stdc++.h>

using namespace std;

#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif


#define ll long long
#define pb push_back
#define st first
#define nd second
#define sz(x) (int)(x).size()
#define all(x) (x).begin(),(x).end()
#define FOR(i,l,r) for(int i=(l);i<=(r);i++)
#define ROF(i,r,l) for(int i=(r);i>=(l);i--)
#define endl '\n'
int inf=1000000007;
ll infl=1000000000000000007;
ll mod=998244353;

const int N=507;

int a[N];
bool is[N];
int DP[N][N][N];
int zkad[N][N][N];

signed main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,m,s=0;
	cin>>n;
	FOR(i,1,n) 
	{
		cin>>a[i];
		s+=a[i];
	}
	sort(a+1,a+n+1,greater<int>());
	cin>>m;
	FOR(i,1,m)
	{
		int x;
		cin>>x;
		is[x]=1;
	}
	FOR(i,0,n) FOR(j,0,s) FOR(l,0,s) DP[i][j][l]=inf;
	DP[1][0][0]=0;
	int ss=0;
	FOR(i,1,n)
	{
		ss+=a[i];
		FOR(j,0,s)
		{
			FOR(l,0,s)
			{
				if(is[i]&&j>=i&&l>0&&DP[i][j-i][l-1]<DP[i][j][l])
				{
					DP[i][j][l]=DP[i][j-i][l-1];
					zkad[i][j][l]=i;
				}
			}
		}
		FOR(j,0,s)
		{
			FOR(l,0,s)
			{
				if(DP[i][j][l]!=inf) debug(i,j,l,DP[i][j][l]);
				int t=max(0,(ss-j+i-1)/i);
				DP[i][j][l]=max(DP[i][j][l],t+l);
				if(DP[i][j][l]!=inf)
				{
					debug(ss,t);
					debug(i,j,l,DP[i][j][l]);
				}
				if(i==n&&j==s&&l>=DP[i][j][l])
				{
					cout<<l<<endl;
					vector<int>V;
					int x=s,y=l;
					ROF(k,n,1)
					{
						while(zkad[k][x][y]==k)
						{
							x-=k;
							y--;
							V.pb(k);
						}
					}
					reverse(all(V));
					vector<pair<int,int>>X;
					FOR(k,1,n) X.pb({a[k],k});
					for(auto x:V) 
					{
						cout<<x<<" ";
						sort(all(X),greater<pair<int,int>>());
						for(int j=0;j<x;j++) 
						{
							cout<<X[j].nd<<" ";
							X[j].st--;
						}
						cout<<endl;
					}
					return 0;
				}
				DP[i+1][j][l]=DP[i][j][l];
			}
		}
	}
	cout<<-1;
	return 0;
}