int difference(TNode<int>* r, int x, int y,int count)
{
    int sum = 1;
    if (r == nullptr)
    {
        return sum;
    }
    if (r->left == nullptr && r->right == nullptr)
    {
        if (count % 2 == 0)
        {
            sum *= r->data;
        }
    }
    sum *= difference(r->left, x, y, count);
    if (r->data >= x && r->data <= y)
    {
        count++;
    }
    sum *= difference(r->right, x, y, count);
    return sum;
}