void copyLocalTreeRecursive(Node *x, RBTree *tree) {
    if (x->right != NIL)
        copyLocalTreeRecursive(x->right, tree);

    if (x->left != NIL)
        copyLocalTreeRecursive(x->left, tree);

    //If we find the key, we add the num_vegades of the local tree to the global tree,
    // if not, we create a new node in the global tree with the info of the local one
    RBData *nodeFound = findNode(tree, x->data->key);
    if (nodeFound) {
        nodeFound->num_vegades += x->data->num_vegades;
    } else {
        RBData *newNode = malloc(sizeof(RBData));
        newNode->key = malloc(sizeof(char *) * strlen(x->data->key));
        strcpy(newNode->key,x->data->key);
        newNode->num_vegades = x->data->num_vegades;
        insertNode(tree, newNode);
    }

}