// In the name of Allah
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef complex<ld> cld;
#define all(x) (x).begin(),(x).end()
#define len(x) ((ll) (x).size())
#define F first
#define S second
#define pb push_back
#define sep ' '
#define endl '\n'
#define Mp make_pair
#define kill(x) cout << x << '\n', exit(0)
#define set_dec(x) cout << fixed << setprecision(x);
#define file_io(x,y) freopen(x, "r", stdin); freopen(y, "w", stdout);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxn = 15000 + 4;
int n, m, sm;
int A[maxn], B[maxn];
vector<bitset<maxn>> dp[maxn];
bitset<maxn> Mx[maxn];
int valx[maxn], par[maxn]; bool ok[maxn];
vector<int> res; vector<pii> lsx;
priority_queue<pii> qu;
void solve() {
cin >> n;
for (int i = 0; i < n; i++) {
cin >> A[i];
qu.push(Mp(A[i], i));
}
cin >> m;
for (int i = 0; i < m; i++) {
cin >> B[i]; ok[B[i]] = 1;
}
for (int i = 0; i < n; i++) {
valx[1]++; valx[A[i] + 1]--;
sm += A[i];
}
for (int i = 1; i <= sm; i++) valx[i] += valx[i - 1];
for (int i = 1; i <= sm; i++) valx[i] += valx[i - 1];
for (int i = 0; i <= sm; i++) {
for (int j = 0; j <= valx[i]; j++) Mx[i][j] = 1;
}
for (int i = 1; i <= sm + 1; i++) dp[i].resize((sm / i) + 1);
dp[sm + 1][0][0] = 1;
for (int i = sm; i >= 1; i--) {
dp[i][0] = dp[i + 1][0];
for (int j = 1; j <= (sm / i); j++) {
if (j < len(dp[i + 1])) dp[i][j] = dp[i + 1][j];
else dp[i][j].reset();
if (ok[i]) {
dp[i][j] |= (dp[i][j - 1] << i); dp[i][j] &= Mx[j];
}
}
}
int i = -1;
for (int j = 1; j <= sm; j++) {
if (dp[1][j][sm]) {
i = j;
break;
}
}
if (i == -1) {
cout << -1 << endl;
return ;
}
int j = i; i = 1;
int x = sm;
while (j > 0) {
if (j < len(dp[i + 1]) && dp[i + 1][j][x]) i++;
else {
res.pb(i);
x -= i; j--;
}
}
reverse(all(res));
cout << len(res) << endl;
for (int x : res) {
cout << x << sep; lsx.clear();
for (int T = 0; T < x; T++) {
auto f = qu.top(); qu.pop();
cout << f.S + 1 << sep; f.F--; lsx.pb(f);
}
for (auto f : lsx) qu.push(f);
cout << endl;
}
}
int main() {
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int T = 1;
while (T--) {
solve();
}
return 0;
}
