import java.util.*;
public class Main
{
    public static void main(String[] args)
    {
        Scanner sc=new Scanner(System.in);
        if(!sc.hasNextInt())
        {
         System.out.print("Invalid input");
            return;   
        }
        int n=sc.nextInt();
        if(n<2)
        {
            System.out.print("Invalid input");
            return;
        }
        int arr[]=new int[n];
        
        for(int i=0;i<n;i++)
        {
            if(!sc.hasNextInt());
            {
             System.out.print("Invalid input");
            return;   
            }
            arr[i]=sc.nextInt();
        }
        int first=Integer.MIN_VALUE;
        int second=Integer.MAX_VALUE;
        for(int num:arr)
            {
                if(num>first)
                {
                    second=first;
                    first=num;
                }
                else if(num<first && num<second)
                {
                    second=num;
                }
            }
            if(second==Integer.MIN_VALUE)
            {
                System.out.print("Invalid input");
                return;
            }
            else
            {
            System.out.print(second);
        }
    }
}