#include<bits/stdc++.h>
#define MAXN 3007
using namespace std;
int n,m,pt,total;
int a[MAXN],b[MAXN],ind[MAXN];
vector< pair<int,int> > v;
vector< vector<int> > w;
int maxs[MAXN],br;
unordered_map<int,int> dp[MAXN][MAXN];
int ff(int pos,int box,int sum){
if(sum<0 or box<1)return 1000000;
if(sum==0)return 0;
if(dp[box][sum][pos]!=0)return dp[box][sum][pos];
dp[box][sum][pos]=ff(pos,box-1,sum);
if(total-sum+b[box]<=maxs[pos] and sum-b[box]>=0){
dp[box][sum][pos]=min(dp[box][sum][pos],ff(pos+1,box,sum-b[box])+1);
}
return dp[box][sum][pos];
}
void solve(int pos,int box,int sum){
if(sum==0)return;
if(ff(pos,box,sum)==ff(pos,box-1,sum)){
solve(pos,box-1,sum); return;
}
br++; v.push_back({b[box],br});
solve(pos+1,box,sum-b[box]);
}
bool cmp(int x,int y){
return a[x]>a[y];
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n;
for(int i=1;i<=n;i++){
cin>>a[i];
total+=a[i];
ind[i]=i;
}
for(int i=1;i<=total;i++){
for(int f=1;f<=n;f++){
maxs[i]+=min(a[f],i);
}
}
cin>>m;
for(int i=1;i<=m;i++){
cin>>b[i];
}
if(ff(1,m,total)>total){
cout<<"-1\n";
return 0;
}
solve(1,m,total);
w.resize(int(v.size()));
sort(ind+1,ind+n+1,cmp);
for(int i=1;i<=n;i++){
sort(v.begin(),v.end());
reverse(v.begin(),v.end());
for(int f=0;f<a[ind[i]];f++){
v[f].first--;
w[v[f].second-1].push_back(ind[i]);
}
}
cout<<w.size()<<"\n";
for(int i=0;i<w.size();i++){
cout<<w[i].size()<<" ";
for(int f:w[i])cout<<f<<" ";
cout<<"\n";
}
return 0;
}
