source_code: import java.util.*;
  
  public class A
  {
      public static void main(String args[])
      {
          Scanner scan = new Scanner(System.in);
          
          int n = scan.nextInt();
          
          int[] a = new int[n];
          
          for(int i=0;i < n;i++)
              a[i] = scan.nextInt();
              
          Arrays.sort(a);
          
          int min = a[0];
          
          for(int i=1;i < n;i++)
          {
              if(a[i] > min)
              {
                  System.out.println(a[i]);
                  return;
              }
          }
          
          System.out.println("NO");
      }
  }
  