source_code: 
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.Arrays;
  import java.util.StringTokenizer;
  
  public class Main {
  
  	public static void main(String[] args) throws NumberFormatException, IOException {
  		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
  		int n = Integer.parseInt(in.readLine());
  		
  		int nums[] = new int[n];
  		StringTokenizer tokenizer = new StringTokenizer(in.readLine(), " ");
  
  		for (int i = 0; i < n; i++) {
  			nums[i] = Integer.parseInt(tokenizer.nextToken());
  		}
  		
  		Arrays.sort(nums);
  		int min = nums[0];
  		int so = -200;
  		for (int i = 1; i < n; i++) {
  			if(nums[i] != min) {
  				so = nums[i];
  				break;
  			}
  		}
  		if(so != -200)
  		System.out.println(so);
  		else
  			System.out.println("NO");
  	}
  }
  