// editor1
import java.util.*;

public class Karthi{
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int arr[] = new int[n];
        int largest, secondLargest;
        boolean flag = false;
        for(int i = 0; i < arr.length; i++) arr[i] = sc.nextInt();
        
        for(int j = 0; j < arr.length-1; j++){
            for(int k = j+1; k < arr.length; k++){
                if(arr[j] > arr[k]){
                    largest = arr[j];
                } 
            }
        }
        
        for(int j = 0; j < arr.length-1; j++){
            for(int k = j+1; k < arr.length; k++){
                if((arr[j] > arr[k]) && (arr[j] == largest)) continue;
                else if(arr[j] > arr[k]) secondLargest = arr[j];
            }
        }
        
        for(int j = 0; j < arr.length-1; j++){
            for(int k = j+1; k < arr.length; k++){
                if(arr[j] == secondLargest){
                    flag = true;
                    break;
                } 
            }
        }
        
        if(arr.length < 2 || !flag){
            System.out.print("Invalid input");
            return;
        }
        
        System.out.print(secondLargest);
    }
}