#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(!newnode){
        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->right,key);
 }
 int main(){
     int n,value,key;
     scanf("%d",&n);
     if(n<0)
     {
         printf("Invalid output");
         return 0;
     }
     struct node* root=NULL;
     for(int i=0;i<n;i++){
         scanf("%d",&value);
         root=insert(root,value);
     }
        scanf("%d",&key);
        if(key<0){
            printf("Invalid input");
            return 0;
        }
        if(search(root,key)){
            printf("found\n");
        }
        else{
            printf("Not found");
            return 0;
        }
     }