#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>
typedef struct Node {
    int data;
    struct Node*left, *right;
    int height;
} Node;
int max(int a,int b) {
    return (a > b) ? a : b;
}
int height(Node *N) {
    if (N == NULL)
    return 0;
    return N->height;
}
Node* newNode(int key) {
    Node* node = (Node*)malloc(sizeof(Node));
    node->data = key;
    node->left = node->right = NULL;
    node->height = 1;
    return node;
}
Node* rightRotate(Node *y) {
    Node *x = y->left;
    Node *T2 = x->right;
    x->right = y;
    y->left = T2;
    y->height = max(height(y->left), height(y->right)) + 1;
    x->height = max(height(x->left), height(x->right)) + 1;
    return x;
}
Node* leftRotate(Node *x) {
    Node *y = x->right;
    Node *T2 = y->left;
    y->left = x;
    x->right = T2;
    x->height = max(height(x->left), height(x->right)) + 1;
    y->height = max(height(y->left), height(y->right)) + 1;
    return y;
}
int getBalance(Node *N) {
    if (N == NULL)
    return 0;
    return height(N->left) - height(N->right);
}
Node* insert(Node* node, int key) {
    if (node == NULL)
    return newNode(key);
    if (key < node->data)
    node->left = insert(node->left, key);
    else if (key > node->data)
    node->right = insert(node->right,key);
    else
    return node;
    node->height = 1 + max(height(node->left), height(node->right));
    int balance = getBalance(node);
    if (balance > 1 && key < node->left->data)
    return rightRotate(node);
    if (balance < -1 && key > node->right->data)
    return leftRotate(node);
    if (balance > 1 && key > node->left->data) {
        node->left = leftRotate(node->left);
        return rightRotate(node);
    }
    if (balance < -1 && key < node->right->data) {
        node->right = rightRotate(node->right);
        return leftRotate(node);
    }
    return node;
}
Node *minValueNode(Node* node) {
    Node* current = node;
    while (current->left != NULL)
    current = current->left;
    return current;
}
Node* deleteNode(Node* root, int key) {
    if (root == NULL)
    return root;
    if (key < root->data)
    root->left = deleteNode(root->left, key);
    else if (key > root->data)
    root->right = deleteNode(root->right, key);
    else {
        if ((root->left == NULL) || (root->right == NULL)) {
            Node *temp = root->left ? root->left : root->right;
            if (temp == NULL) {
                temp = root;
                root = NULL;
            } else
            *root = *temp;
            free(temp);
        } else {
            Node* temp = minValueNode(root->right);
            root->data = temp->data;
            root->right = deleteNode(root->right, temp->data);
        }
    }
    if (root == NULL)
    return root;
    root->height = 1 + max(height(root->left), height(root->right));
    int balance = getBalance(root);
    if (balance > 1 && getBalance(root->left) >= 0)
    return rightRotate(root);
    if (balance > 1 && getBalance(root->left) < 0) {
        root->left = leftRotate(root->left);
        return rightRotate(root);
    }
    if (balance < -1 && getBalance(root->right) <= 0)
    return leftRotate(root);
    if (balance < -1 && getBalance(root->right) > 0) {
        root->right = rightRotate(root->right);
        return leftRotate(root);
    }
    return root;
}
void preOrder(Node *root) {
    if (root != NULL) {
        printf("%d", root->data);
        preOrder(root->left);
        preOrder(root->right);
    }
}
int main() {
    int n, x;
    if (scanf("%d %d", &n, &x) != 2 || n < 0) {
        printf("Invalid input");
        return 0;
    }
    int ids[20];
    for (int i = 0;i < n; i++) {
        if (scanf("%d", &ids[i]) != 1) {
            printf("Invalid input");
            return 0;
        }