#include <bits/stdc++.h>
//#define int long long
using namespace std;
const int N = 1.5e4 + 42;
vector<int> boite;
vector<bitset<N>> dp[N];
int n, m, a[N], sz[N], prefix[N];
void remonter(int i, int j, int sum) {
if(sum == 0)
return;
if(dp[i-1][j][sum - sz[j]]) {
boite.push_back(-sz[j]);
remonter(i-1, j, sum - sz[j]);
} else {
remonter(i, j+1, sum);
}
}
void printSol() {
vector<int> id[N];
vector<pair<int, int>> vals;
for(int i = 0; i < n; i++)
vals.push_back({-a[i], i});
sort(vals.begin(), vals.end());
for(int i = 0; i < n; i++)
for(int j = 0; j < a[vals[i].second]; j++)
id[j].push_back(vals[i].second+1);
queue<int> ids;
for(int i = 0; i < N; i++)
for(int j : id[i])
ids.push(j);
sort(boite.begin(), boite.end());
cout << boite.size() << '\n';
for(int b : boite) {
b = -b;
cout << b << ' ';
for(int j = 0; j < b; j++) {
cout << ids.front() << ' ';
ids.pop();
}
cout << '\n';
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n;
for(int i = 0; i < n; i++) {
cin >> a[i];
for(int j = 0; j < N; j++)
prefix[j] += min(j, a[i]);
}
cin >> m;
dp[0].resize(m);
dp[0][m-1] = true;
for(int i = 0; i < m; i++)
cin >> sz[i];
int sum = prefix[N-1];
for(int i = 0; i <= sum; i++) {
for(int j = m-1; j >= 0; j--)
if(i * sz[j] <= sum) {
dp[i+1].resize(j+1);
j = 0;
}
for(int j = m-1; j >= 0; j--)
if(i * sz[j] <= sum) {
dp[i][j] <<= (N-prefix[i]-1);
dp[i][j] >>= (N-prefix[i]-1);
if(dp[i][j][sum]) {
remonter(i, j, sum);
printSol();
return 0;
}
if(j > 0)
dp[i][j-1] |= dp[i][j];
if((i+1) * sz[j] <= sum)
dp[i+1][j] |= (dp[i][j] << sz[j]);
}
}
cout << -1 << '\n';
}
