import java.util.*;
public class array{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        if(n<2){
            System.out.println("Invalid input");
        }
        int[] arr=new int[n];
        for(int i=0;i<n;i++){
          arr[i]=sc.nextInt();
        }
        for(int i=0;i<n-1;i++){
            if(arr[i]==arr[a+1]){
                System.out.println("Invalid input");
            }
            if(arr[i]>arr[i+1]){
                int temp=arr[i];
                arr[i]=arr[i+1];
                arr[i]=temp;
            }
            
        }
        System.out.println(arr[n-2]);
    }
}