#include <algorithm>
#include <iostream>
#include <climits>
#include <fstream>
#include <random>
#include <time.h>

using namespace std;

const int MAXN = 1e6;

mt19937 rnd(22);

struct Stick
{
    int64_t h, p;
    int ind;
};

int n;
int64_t b;
Stick sticks[MAXN + 5];

int main()
{
    #ifndef __LOCAL__
        ifstream cin("sticks.in");
        ofstream cout("sticks.out");
    #endif

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int64_t bestScore = numeric_limits<int64_t>::max();
    vector<vector<int>> bestSetup;

    cin >> n >> b;
    for (int i = 0; i < n; i++)
    {
        cin >> sticks[i].h;
        sticks[i].ind = i;
    }
    for (int i = 0; i < n; i++)
    {
        cin >> sticks[i].p;
    }

    int startExecution = clock();

    while (clock() - startExecution < 3 * 1000)
    {
        shuffle(sticks, sticks + n, rnd);

        int64_t lastSum = 0;
        vector<vector<int>> setup = {{}};

        int64_t penalty = 0;
        for (int i = 0; i < n; i++)
        {
            if (lastSum >= b)
            {
                lastSum = 0;
                setup.push_back({});
            }

            if (lastSum + sticks[i].h > b)
            {
                penalty += sticks[i].p;
            }

            lastSum += sticks[i].h;
            setup.back().push_back(sticks[i].ind);
        }

        int64_t k = setup.size();
        int64_t score = k*k*k + penalty;

        if (score < bestScore)
        {
            bestScore = score;
            bestSetup = setup;
        }
    }

    cout << bestSetup.size() << '\n';
    for (const vector<int> &hole : bestSetup)
    {
        cout << hole.size();
        for (int ind : hole)
        {
            cout << " " << ind + 1;
        }
        cout << '\n';
    }
}