bool unload(void)
{
    // TODO
    bool suc = false ;
    for (int i = 0 ; i < N ; i ++ )
    {
        while (table[i]->next != NULL)
        {
            node *F = table[i]-> next ;
            free(table[i]) ;
            table[i] = F ;
        }
        suc = true ;

    }

    if (suc == true)
    {
        return true ;
    }
    else
    {
        return false;
    }


}