free_all(students,courses);
    return 0;
}

void free_all(slist *sl, clist *cl){
    clist *tempCL;
    slist *tempSL;

    if(cl){                         // only if it is necessary, clist release for every student
        tempSL=cl->info->students;
        while(tempSL){
            free_clist(tempSL->info->courses);
            tempSL=tempSL->next;
        }
    }

    tempCL=cl;              // releasing slists for every course
    while(tempCL){
        free_slist(tempCL->info->students);
        tempCL=tempCL->next;
    }


    tempSL=sl;
    while(tempSL){                  //strings release
        free(tempSL->info->name);
        tempSL=tempSL->next;
        var--;
    }

    tempCL=cl;
    while(tempCL){
        free(tempCL->info->title);
        tempCL=tempCL->next;
        var--;
    }

    tempSL=sl;
    while(tempSL){              // "students card" release
        free(tempSL->info);
        tempSL=tempSL->next;
        var--;
    }

    tempCL=cl;
    while(tempCL){              // "course card" release
        free(tempCL->info);
        tempCL=tempCL->next;
        var--;
    }

    free_clist(cl);     // releasing main course list and main student list
    free_slist(sl);

    printf("\n malloc: %d\n", var);

}

void free_clist(clist *head){
    if(head==NULL)
        return;
    free_clist(head->next);
    free(head);
    var--;
}

void free_slist(slist *head){
    if(head==NULL)
        return;
    free_slist(head->next);
    free(head);
    var--;
}