#include<stdio.h>
#include<stdlib.h>
struct node{
    int data;
    struct node*left;
    struct node*right;   
};
struct node*create(int data){
    struct node*newnode=(struct node*)malloc(sizeof(struct node) );
if(!newif(!node){
    printf("memory allocation failed\n");
    exit(1);
    
}   
newnode->data=data;
newnode->left=newnode->right=NULL;
return newnode;
}
struct node*insert(struct node*root,int data){
    if(root==NULL)
    return create(data);
    if(data<root->data)
    root->left=insert(root->left,data);
    else if(data>root->data)
    root->right=insert(root->right,data);
    return root;
}
int search(struct node*root,int key)
{
    if(root==NULL)
    return 0;
    if(root->data==key)
    return 1;
    else if(key<root->data)
    return search(root->left,key);
    else
    return search(root->right,key);
    
}
int main()
{
    int n,value,key;
    scanf("%d",&n);
    if(n<=0)
    {
        printf("invalid input");
        return 0;
        
    }
    struct node*root=NULL;
    for(int i=0;i<n;i++){
        scanf("%d",&value);
        root=insert(root,value);
        
    }
    scanf("%d",&key);
    if(search(root,key))
    printf("found");
    else
    printf("not found");
    return 0;
}