#pragma GCC optimize("O3,unroll-loops")
#include<cstdio>
#include<algorithm>
#include<vector>
using namespace std;
const int o=15010;
int n,m,a[o],a_[o],b[o],p[o],s,f[o][o],cnt[o],st[o],tp,q[o];vector<int> vec[o];
inline bool cmp(int A,int B){return a[A]>a[B];}
inline bool Cmp(int A,int B){return st[A]>st[B];}
int main(){
	scanf("%d",&n);
	for(int i=1;i<=n;++i) scanf("%d",&a[i]),p[i]=i,s+=a[i];
	sort(p+1,p+n+1,cmp);
	scanf("%d",&m);
	for(int i=1;i<=m;++i) scanf("%d",&b[i]);
	for(int i=n;i;--i) a_[i]=a_[i+1]+a[p[i]];
	f[m+1][0]=1;
	for(int i=m,j,L=0,R=s,l,r,lim;i;--i,L=l,R=r) for(j=L,l=s,r=0;j<=R;++j) if(f[i+1][j]){
		lim=(s-j)/b[i];
		for(int k=b[i];k>b[i-1];--k) lim=min(lim,(a_[k]-j)/(b[i]-k+1));
		if(f[i+1][j]-1>lim) continue;
		l=min(l,j+(b[i]-b[i-1])*(f[i+1][j]-1));r=max(r,j+(b[i]-b[i-1])*lim);
		for(int k=f[i+1][j]-1,t=j+(b[i]-b[i-1])*k;k<=lim;++k,t+=b[i]-b[i-1]) f[i][t]=k+1;
	}
	if(!f[1][s]){printf("-1");return 0;}
	printf("%d\n",f[1][s]-1);
	for(int i=1,j=s;i<=m;++i) cnt[i]=--f[i][j],j-=(b[i]-b[i-1])*f[i][j];
	for(int i=1;i<=m;++i) for(int j=cnt[i]-cnt[i+1];j--;) st[++tp]=b[i];
	for(int i=1;i<=tp;++i) q[i]=i;
	for(int i=1;i<=n;++i){
		nth_element(q+1,q+a[p[i]],q+tp+1,Cmp);
		for(int j=1;j<=a[p[i]];++j) vec[q[j]].push_back(p[i]),--st[q[j]];
	}
	for(int i=1;i<=tp;++i,putchar('\n')){
		printf("%llu ",vec[i].size());
		for(int j=vec[i].size();j--;) printf("%d ",vec[i][j]);
	}
	return 0;
}