void removeNode(Node * bst,Node n) {
    if (n->left == NULL && n->right == NULL){
        flatten(bst, n, NULL);
    } else if (n->left == NULL && n->right != NULL){
        flatten(bst, n, n->right);
    } else if (n->left != NULL && n->right == NULL){
        flatten(bst, n, n->left);
    } else  {
        // 2 stopien
        Node wsk = minNode(n->right);
        n->key = wsk->key;

        flatten(bst, wsk, wsk->right);
        n = wsk;
    }

    free(n);
}