int getNode(SinglyLinkedListNode* llist, int positionFromTail) {
    // Check for edge cases: empty list or invalid position
    if (llist == nullptr || positionFromTail < 0) {
        // Return an appropriate error or special value.
        // For this example, we return a default value or handle as an error.
        // In a real-world scenario, you might throw an exception.
        return -1; 
    }

    auto slow = llist;
    auto fast = llist;

    // Move 'fast' pointer 'positionFromTail' steps ahead
    for (int i = 0; i < positionFromTail; ++i) {
        if (fast == nullptr) {
            // The position is out of bounds
            return -1;
        }
        fast = fast->next;
    }

    // Now, move both pointers until 'fast' reaches the end
    while (fast->next != nullptr) {
        slow = slow->next;
        fast = fast->next;
    }

    return slow->data;
}