get values from a nested dictionary using lambda values of the dictionary are ArrayList of ArrayList

Question

I need to retrieve values from dictionary which stores a ArrayList which in turn has an ArrayList This second ArrayList has int array stored . Now how can I retrieve those integer values. `

        Dictionary<int, ArrayList> obj = new Dictionary<int, ArrayList>();

        ArrayList objList1 = new ArrayList();

        ArrayList objList2 = new ArrayList();

        ArrayList objList3 = new ArrayList();

        Int32[] a1 = new Int32[5] {11, 21, 32, 43, 50 };
        Int32[] b1 = new Int32[5] { 123, 2321, 3212, 4983, 5760 };
        Int32[] c1 = new Int32[5] { 1341, 2991, 3552, 4663, 5880 };

        objList2.Add(a1);
        objList2.Add(b1);
        objList2.Add(c1);



        objList1.Add(objList2);
        objList1.Add(objList3);

        obj.Add(1, objList1);
        obj.Add(2, objList3);`

this could be done easily with List. I trying it solve with ArrayList. Firstly is it possible? Thanks in advance.