#include<stdio.h>
#include<stdlib.h>
struct TreeNode{
    int data;
    struct TreeNode*left,*right;
};
struct TreeNode*createNode(int val){
    struct TreeNode*newNode=(struct TreeeNode*)malloc(sizeof(struct TreeNode));
    newNode->data=val;
    newNode->left=newNode->right=NULL;
    return newNode;
}
struct TreeNode* insert(struct TreeNode*root,int val){
    if(root==NULL)
    
        return createNode(val);
    
    if(val<root->data)
    
       root->left=insert(root->left,val);
    
    else
       root->right=insert(root->right,val);
    
    return root;
    
}
int search(struct TreeNode*root,int key)
{
    if(root==NULL)
        return 0;
    if(root->data==key)
     return 1;
     if(key<root->data)
     return search(root->left,key);
     return search(root->right,key);
}
int main()
{
    int n;
    if(scanf("%d",&n)!=1)
    return 0;
    if(n<=0)
    {
        printf("Invaild input");
        return 0;
    }
    struct TreeNode*root=NULL;
    for(int i =0;i<n;i++)
    {
        int x;
        scanf("%d",&x);
        root=insert(root,x);
    }
    int target;
    scanf("%d",&target);
    if(search(root,target))
    printf("found");
    else
    printf("not found");
    return 0;
    
}