#include <bits/stdc++.h>
    
using namespace std;
    
typedef long long ll;
const int  N = 2e5 + 12, MOD = (int)1e9 + 7;

int n, m, b[N];
vector<pair<int,int>> a;
int res = -1;
vector<vector<int>> cur, ans;
void go(vector<pair<int, int>> x, int it) {
    sort(x.begin(), x.end());
    reverse(x.begin(), x.end());
    while(!x.empty() && x.back().first == 0) {
        x.pop_back();
    }
    if(x.empty()) {
        if(res == -1 || res > (int)cur.size()) {
            res = (int)cur.size();
            ans = cur;
        }
        return;
    }
    for(int i = it; i >= 1; i--) {
        if(x.size() < b[i]) continue;
        int f = x[b[i] - 1].first;
        vector<pair<int,int>> bf = x;
        int c = 0;
        while(true) {
            vector<int> t;
            if(x[b[i] - 1].first == 0) break;
            for(int j = 0; j < b[i]; j++) {
                t.push_back(x[j].second);
                x[j].first--;
            }
            c++;
            cur.push_back(t);
            sort(x.rbegin(), x.rend());
        }
        go(x, i);
        while(c--) {
            cur.pop_back();
        }
        x = bf;
    }
}

void test() {
    cin >> n;
    for(int i = 1; i <= n; i++) {
        int x;
        cin >> x;
        a.push_back({x, i});
    }
    cin >> m;
    for(int i = 1;i <= m; i++) {
        cin >> b[i];
    }
    go(a, m);
    if(res == -1) {
        cout << -1 << '\n';
        return;
    }
    cout << res << '\n';
    for(auto i:ans) {
        cout << (int)i.size() << ' ';
        for(int j:i) {
            cout << j << ' ';
        }
        cout << '\n';
    }
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0); 
    
    int t = 1; 
    // cin >> t;
    
    while(t--) 
        test();
    return 0;
}