import java.io.*;
import java.util.*;

public class three 
{
	
	public static void main(String[] args) throws IOException
	{
		BufferedReader bf = new BufferedReader(new FileReader("DATA3.txt"));
		PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("OUT3.txt")));
		
		for(int a = 0; a < 5; a++)
		{
			int set = Integer.parseInt(bf.readLine());
			int nums[] = new int[set];
			
			for (int i = 0; i < set; i++)
				nums[i] = Integer.parseInt(bf.readLine());
			
			int counter = 1;
			
			for (int i = 0; i < set + 1; i++)
			{
				if (i > nums.length - 1)
				{
					out.println(counter);
					break;
				}
				if (nums[i] != counter)
				{
					out.println(counter);
					break;
				}
				else
					counter++;
			}
		}
		out.close();
		System.exit(0);
	}

}