#include<iostream>
#include<cstdio>
#include<algorithm>
#define N 15000
using namespace std;
int read()
{
    char c=0;
    int sum=0;
    while (c<'0'||c>'9') c=getchar();
    while ('0'<=c&&c<='9') sum=sum*10+c-'0',c=getchar();
    return sum;
}
int n,m,rst,a[N+1],b[N+1],cnt[N+1],cnts[N+1],p[N+1];
short dp[N+1][N+1],pv[N+1][N+1];
bool cmp(int x,int y)
{
    return a[x]>a[y];
}
int main()
{
    int res=0;
    n=read();
    for (int i=1;i<=n;++i) a[i]=read(),res+=a[i],cnt[a[i]]++;
    for (int i=res-1;i>=1;--i) cnt[i]+=cnt[i+1];
    for (int i=2;i<=res;++i) cnt[i]+=cnt[i-1];
    m=read();
    for (int i=1;i<=m;++i) b[i]=read();
    sort(b+1,b+m+1),dp[0][0]=m;
    for (int i=1;i<=res;++i)
    {
	for (int j=0;j<=cnt[i];++j)
	    if (dp[i-1][j])
	    {
		for (int k=1;j+b[k]<=cnt[i]&&k<=dp[i-1][j];++k)
		    if (k>dp[i][j+b[k]])
			dp[i][j+b[k]]=k,pv[i][j+b[k]]=k;
	    }
	if (dp[i][res])
	{
	    printf("%d\n",i);
	    for (int j=i;j>=1;--j) cnts[j]=b[pv[j][res]],res-=b[pv[j][res]];
	    for (int j=1;j<=i;++j)
	    {
		for (int k=1;k<=n;++k) p[k]=k;
		sort(p+1,p+n+1,cmp);
		printf("%d ",cnts[j]);
		for (int k=1;k<=cnts[j];++k) printf("%d ",p[k]);
		for (int k=1;k<=cnts[j];++k) a[p[k]]--;
		puts("");
	    }
	    return 0;
	}
    }
    puts("-1");
    return 0;
}