#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;
int n, m, t;
int main()
{
#ifdef _CONSOLE
freopen("input.txt", "r", stdin);
#endif
int n;
scanf("%d", &n);
vector<int> vi(n);
for (int i = 0; i < n; i++){
scanf("%d", &vi[i]);
}
sort(vi.begin(), vi.end());
vi.resize(unique(vi.begin(), vi.end()) - vi.begin());
scanf("%d", &m);
vector<int>::iterator itor = lower_bound(vi.begin(), vi.end(), vi.size());
if (itor == vi.end()){
printf("%d\n", (m - n) + (vi.size() - 1));
}
else{
if(*itor + vi.size() - 1 <= m )
printf("%d\n", *itor);
else{
printf("%d\n", (m - n) + (vi.size() - 1));
}
}
}
