static long[][] ans;

    static long buyMaximumProducts(int n, long k, int[] a) {
        int size = a.length;
        ans = new long[size][size + 1];
        for (int i = 0; i < size; i++) {
            for (int j = 0; j <= size; j++) {
                ans[i][j] = -1;
            }
        }

        return func(n, 0, 0, k, a);
    }

    static long func(int n, int j, int index, long k, int[] a) {
        System.out.println(j);

        if (index == n || k == 0 || k < 0)
            return 0;

        if (ans[index][j] != -1) {
            return ans[index][j];
        }

        for (int i = 0; i <= index; i++) {
            ans[index][i] = Math.max(ans[index][j], func(n, i, index + 1, k - i
                    * a[index], a) + i);
        }

        return ans[index][j];
    }