Poly Poly::pick(const Poly & p,int conv)
{
    Poly np;
    Term t;
    Node * curr = head;
    Node * curp = p.head;
    if(conv != 0)
    {
        while(curr)
        {
            if(curr->data <= t)
                remove(curr->data);
            else
                np += curr->data;
            curr =  curr->next;
        }
        while(curp)
        {
            if(conv == -1)
            {
                if(curp->data <= t)
                    remove(curp->data);
                else
                {
                t = curp->data-=conv;
                np += t;
                }
            }
            else if(conv == 1)
            {
                if(curp->data <= t)
                    remove(curp->data);
                else
                np += curp->data;
            }
            curp =  curp->next;
        }
    }
    else
    {
        while(curp)
        {
            while(curr)