#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin ("cautbin.in");
ofstream fout ("cautbin.out");
 

int n,m,a[100005],p,x,last;

int st,dr,med,ok=0,rez,mij,c;
int main()
{
    cin>>n;
    for(int i=1;i<=1;i++)
        cin>>a[i];
   	sort(a+1,a+n+1);
 		cin>>x;
    st=1;
    dr=n;
    while(st<dr)
    {
        med=(st+dr)/2;
        if(x==a[med])
        {
            rez=a[med];
            ok=1;
        }
        if(x>a[med])
            {
            	st=med+1;//cout<<med<<" ";
            }
        if(x<a[med])
            {
            	dr=med-1;//cout<<med<<" ";
            }
    }
    while(st<=dr) {
        mij=(st+dr)/2;
        if(x==a[mij]) {
            if (c==0) {
                last=mij;
                st=mij+1;
            }
            if (c==1) {
                last=mij;
                st=mij+1;
            }
            if (c==2) {
                last=mij;
                dr=mij-1;
            }
         }
        if(x<a[mij]) {
            dr=mij-1;
            if (c==2) {
                last=mij;
            }
        }
        if(x>a[mij]) {
            st=mij+1;
            if (c==1) {
                last=mij;
            }
        }
    }
    if(ok=1)
        cout<<rez;
	else 
	cout<<-1; 
	cout<<last;
    return 0;
}