#include <bits/stdc++.h>
using namespace std;
const int N = 500;
const int S = 15000;
int n, m, a[N + 10], b[N + 10];
int dp[N + 10], par[N + 10];
pair<int, int> cnt[S + 10];
vector<int> vec[S + 10];
void readInput() {
cin >> n;
for (int i = 1; i <= n; i++)
cin >> a[i];
cin >> m;
for (int i = 1; i <= m; i++)
cin >> b[i];
}
void calcDP() {
dp[0] = 1;
for (int i = 1; i <= m; i++)
for (int j = b[i]; j <= n; j++)
if (dp[j - b[i]] && (!dp[j] || dp[j - b[i]] + 1 < dp[j])) {
dp[j] = dp[j - b[i]] + 1;
par[j] = b[i];
}
}
void solveSub1() {
if (dp[n] == 0) {
cout << -1 << flush;
return;
}
vector<int> vec;
int pnt = n;
while (pnt) {
vec.push_back(par[pnt]);
pnt -= par[pnt];
}
int tmp = 1;
cout << vec.size() << '\n';
for (auto x: vec) {
cout << x << ' ';
for (int i = 1; i <= x; i++) {
cout << tmp << ' ';
tmp++;
}
cout << '\n';
}
}
void solveSub2() {
int sum = 0;
for (int i = 1; i <= n; i++)
sum += a[i];
if (sum % b[1]) {
cout << -1 << flush;
return;
}
int ans = sum / b[1];
for (int i = 1; i <= ans; i++)
cnt[i] = {b[1], i};
for (int i = 1; i <= n; i++) {
for (int j = ans; j >= 1; j--)
if (a[i] && cnt[j].first) {
a[i]--;
cnt[j].first--;
vec[cnt[j].second].push_back(i);
}
if (a[i]) {
cout << -1 << flush;
return;
}
sort(cnt + 1, cnt + ans + 1);
}
cout << ans << '\n';
for (int i = 1; i <= ans; i++) {
cout << b[1] << ' ';
for (auto x: vec[i])
cout << x << ' ';
cout << '\n';
}
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
readInput();
if (*max_element(a + 1, a + n + 1) == 1) {
calcDP();
solveSub1();
}
else if (m == 1)
solveSub2();
return 0;
}
