#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9;
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int n, m;
cin >> n;
vector<int> a(n);
for (int &i : a) { cin >> i; }
cin >> m;
vector<int> b(m);
for (int &i : b) { cin >> i; }
vector<int> type;
for (int i = 0; i < n; ++i) {
for (int j = 0; j < a[i]; ++j) { type.push_back(i); }
}
int tot = accumulate(a.begin(), a.end(), 0);
// let dp[mask] = minimum number of boxes to divide the cookies in mask
vector<int> dp(1 << tot, inf);
dp[0] = 0;
for (int mask = 1; mask < 1 << tot; ++mask) {
vector<vector<int>> _with_type(n);
for (int i = 0; i < tot; ++i) {
if (mask & 1 << i) {
_with_type[type[i]].push_back(i);
}
}
for (int &s : b) {
vector<int> box;
auto with_type = _with_type;
vector<int> ord(n);
iota(ord.begin(), ord.end(), 0);
sort(ord.begin(), ord.end(), [&](int i, int j) { return with_type[i].size() > with_type[j].size(); });
int nmask = mask, rem = 0;
for (int &type : ord) {
if (rem == s || with_type[type].empty()) { break; }
int idx = with_type[type].back();
with_type[type].pop_back();
box.push_back(type);
nmask ^= 1 << idx;
rem++;
}
if (rem == s) {
if (1 + dp[nmask] < dp[mask]) {
dp[mask] = 1 + dp[nmask];
}
}
}
}
int mask = (1 << tot) - 1;
if (dp[mask] == inf) {
cout << "-1\n";
return 0;
}
cout << dp[mask] << '\n';
vector<vector<int>> ans;
while (mask) {
vector<vector<int>> _with_type(n);
for (int i = 0; i < tot; ++i) {
if (mask & 1 << i) {
_with_type[type[i]].push_back(i);
}
}
for (int &s : b) {
vector<int> box;
auto with_type = _with_type;
vector<int> ord(n);
iota(ord.begin(), ord.end(), 0);
sort(ord.begin(), ord.end(), [&](int i, int j) { return with_type[i].size() > with_type[j].size(); });
int nmask = mask, rem = 0;
for (int &type : ord) {
if (rem == s || with_type[type].empty()) { break; }
int idx = with_type[type].back();
with_type[type].pop_back();
box.push_back(type);
nmask ^= 1 << idx;
rem++;
}
if (rem == s && 1 + dp[nmask] == dp[mask]) {
ans.push_back(box);
mask = nmask;
break;
}
}
}
for (auto &box : ans) {
cout << box.size() << ' ';
for (int &i : box) { cout << i + 1 << ' '; }
cout << '\n';
}
}
