#include<iostream>
#include<set>
#include<vector>
#include<algorithm>
#include<bitset>
#include<unordered_map>
#include<map>
using namespace std;
const int MAX_N=3003;
int n,m;
int a[MAX_N];
int b[MAX_N];
bitset<MAX_N>bor[MAX_N];
unordered_map<int,bitset<MAX_N>>dp[MAX_N];
int minsum[MAX_N];
vector<int>boxes[MAX_N];
vector<int>box;
void constructans()
{
sort(box.rbegin(),box.rend());
set<pair<int,int>>s;
for(int i=1;i<=n;i++)s.insert({a[i],i});
int j=0;
for(int B:box)
{
j++;
vector<int>curbox;
for(auto [sz,type]:s)curbox.push_back(type);
for(int i=1;i<=B;i++)
{
boxes[j].push_back(curbox.back());
s.erase({a[curbox.back()]--,curbox.back()});
if(a[curbox.back()])s.insert({a[curbox.back()],curbox.back()});
curbox.pop_back();
}
}
cout<<box.size()<<"\n";
for(int i=1;i<=box.size();i++)
{
cout<<boxes[i].size()<<" ";
for(int x:boxes[i])cout<<x<<" ";
cout<<"\n";
}
}
int main ()
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin>>n;
int all=0;
for(int i=1;i<=n;i++)
{
cin>>a[i];
all+=a[i];
}
for(int boxes=1;boxes<=all;boxes++)
{
for(int i=1;i<=n;i++)
{
minsum[boxes]+=min(boxes,a[i]);
}
}
bor[0][0]=1;
for(int sum=1;sum<=all;sum++)
{
bor[sum][sum]=1;
bor[sum]|=bor[sum-1];
}
cin>>m;
for(int i=1;i<=m;i++)
{
cin>>b[i];
}
sort(b+1,b+m+1);
reverse(b+1,b+m+1);
dp[0][0][0]=1;
for(int id=1;id<=m;id++)
{
for(int boxes=0;boxes<=all;boxes++)
{
if(dp[id-1].find(boxes)!=dp[id-1].end() && dp[id-1][boxes].any())
{
dp[id][boxes]|=dp[id-1][boxes];
}
if(boxes)
{
int sm=minsum[boxes]-b[id];
if(sm>=0)
{
if(dp[id].find(boxes-1)!=dp[id].end() && ((dp[id][boxes-1])&(bor[sm])).any())
{
dp[id][boxes]|=(((dp[id][boxes-1])&(bor[sm]))<<b[id]);
}
}
}
}
}
int ans=-1;
for(int boxes=1;boxes<=all;boxes++)
{
if(dp[m][boxes][all])
{
ans=boxes;
break;
}
}
if(ans==-1)
{
cout<<-1<<"\n";
return 0;
}
int id=m,boxes=ans,sum=all;
while(boxes)
{
if(dp[id][boxes-1][sum-b[id]])
{
box.push_back(b[id]);
boxes--;
sum-=b[id];
}
else id--;
}
constructans();
return 0;
}
