#include <bits/stdc++.h>
using namespace std;

struct stc{
    int height;
    int penalty;
    int index;
};

int n, b;
stc sticks[1000005];

int k;
int currentLen = 0;
vector<int> holes[1000005];

int main()
{
    freopen("sticks.out", "w", stdout);
    freopen("sticks.in", "r", stdin);
    scanf("%d %d", &n, &b);

    for (int i = 0; i < n; ++i)
    {
        sticks[i].index = i;
        scanf("%d", &sticks[i].height);
    }

    for (int i = 0; i < n; ++i)
    {
        scanf("%d", &sticks[i].penalty);
    }

    
    for (int i = 0; i < n; i++)
    {
        if (currentLen != 0 && currentLen + sticks[i].height > b)
        {
            currentLen = 0;
            k++;
        }
        holes[k].push_back(sticks[i].index);
        currentLen += sticks[i].height;
    }

    printf("%d\n", k+1);
    for (int i = 0; i <= k; i++)
    {
        printf("%d ", holes[i].size());
        for (int j = 0; j < holes[i].size(); j++)
        {
            printf("%d ", holes[i][j]+1);
        }
        printf("\n");
    }



    return 0;
}