#include <bits/stdc++.h>
using namespace std;

int q(int w[],int n,int x){
    int l = 0,r = n - 1;
    while(l <= r){
        int mid = (l + r) / 2;
        if(w[mid] == x){
            return mid;
        }
        if(w[mid] < x){
            l = mid + 1;
        }else {
            r = mid - 1;
        }
    }

    return -1;
}

int main(){
    
    int n,x;
    cin >> n;
    int w[n];
    for (int i = 0;i < n;i++){
        cin >> w[i];
    }
    cin >> x;
    int z = q(w,n,x);
    if(z != -1){
        cout << x;
    }else {
        cout << "no";
    }
    return 0;
}