#include <iostream>
#include <fstream>
#include <string>
#include <string.h>
#include <queue>
#include <stdio.h>
#include <algorithm>
#include <vector>
#include <stack>
#include <map>
#include <set>
#include <limits.h>
typedef long long ll;
using namespace std;
ll n, m, t;
int main()
{
#ifdef _CONSOLE
freopen("input.txt", "r", stdin);
#endif
ll n;
scanf("%d", &n);
vector<ll> vi(n);
for (ll i = 0; i < n; i++){
scanf("%d", &vi[i]);
}
scanf("%d", &m);
if (m <= n){
printf("%d\n", vi[m - 1]);
return 0;
}
sort(vi.begin(), vi.end());
vi.resize(unique(vi.begin(), vi.end()) - vi.begin());
vector<ll>::iterator itor = lower_bound(vi.begin(), vi.end(), vi.size());
if (itor == vi.end()){
printf("%lld\n", (m - n) + (vi.size() - 1)); // 무한
}
else{
if((*itor - vi.size() + 1) + n <= m) // 아닐때
printf("%lld\n", *itor);
else{
printf("%lld\n", (m - n) + (vi.size() - 1));
}
}
}
