#include <bits/stdc++.h>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define ep insert
#define endl '\n'
#define elif else if
#define pow pwr
#define sqrt sqrtt
#define int long long
#define ll long long
typedef unsigned long long ull;
using namespace std;
const int N=505;
int dp[N],a[N],b[N],n,m;
int32_t main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
dp[0]=0;vector<int> v;
for (int i=1;i<N;i++) dp[i]=1e6;
cin>>n;
for (int i=1;i<=n;i++) cin>>a[i],v.pb(i);
cin>>m;
for (int i=1;i<=m;i++) cin>>b[i];
for (int i=1;i<=n;i++) for (int j=1;j<=m;j++) if (i-b[j]>=0) dp[i]=min(dp[i],dp[i-b[j]]+1);
if (dp[n]>=1e6){
cout<<-1<<endl;
return 0;
}
cout<<dp[n]<<endl;
int x=n;
while (x){
int y=0;
for (int j=1;j<=m;j++) if (x-b[j]>=0 && dp[x-b[j]]+1==dp[x]) y=j;
cout<<b[y]<<' ';
for (int i=0;i<b[y];i++) cout<<v.back()<<' ',v.ppb();
cout<<endl;
x-=b[y];
}
return 0;
}
