#include<bits/stdc++.h>

using namespace std;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef long long ll;
#define int ll
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define pb push_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mispertion ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define F first
#define S second
#define getlast(s) (*s.rbegin())
#define debg cout << "OK\n"

const ld PI = 3.1415926535;
const int N = 1e3+5;
const int M = 50 + 1;
const int mod = 1e9+7;
const int infi = 1e15;
const ll infl = LLONG_MAX;
const int P = 31;

int mult(int a, int b) {
    return a * 1LL * b % mod;
}

int sum(int a, int b) { 
    if (a + b < 0)
        return a + b + mod;
    if (a + b >= mod)
        return a + b - mod;
    return a + b;
}

ll binpow(ll a, ll n) {
    if (n == 0)
        return 1;
    if (n % 2 == 1) {
        return binpow(a, n - 1) * a % mod;
    } else {
        ll b = binpow(a, n / 2);
        return b * b % mod;
    }
}

int n, a[N], m, b[N], dp[N];

void solve(){
    cin >> n;
    int sm = 0, mx = -1;
    for(int i = 1; i <= n; i++){
        cin >> a[i];
        sm += a[i];
        mx = max(mx, a[i]);
    }
    cin >> m;
    for(int i = 1; i <= m; i++)
        cin >> b[i];
    if(sm % b[1] != 0){
        cout << -1 << '\n';
        return;
    }
    if((sm / b[1]) < mx){
        cout << -1 << '\n';
        return;
    }
    set<pii> st;
    for(int i = 1; i <= n; i++){
        st.insert({a[i], i});
    }
    vector<vector<int>> ans = {};
    while(sz(st) > 0){
        auto it = st.rbegin();
        vector<int> da = {};
        vector<pii> td = {};
        for(int i = 0; i < b[1]; i++, it++){
            da.pb(it->S);
            td.pb(*it);
        }
        for(auto e : td){
            st.erase(e);
            if(e.F != 1)
                st.insert({e.F - 1, e.S});
        }
    }
    cout << sz(ans) << '\n';
    for(auto e : ans){
        cout << sz(e) << ' ';
        for(auto e1 : e){
            cout << e1 << ' ';
        }
        cout << '\n';
    }
}   

signed main() {
    mispertion;
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    return 0;
}