import java.util.*;

public class Solution {

    public static String read(int n, int []book, int target){

        // Write your code here.

        Arrays.sort(book);

        int left = 0;

        int right = n-1;

        while(left<right)

        {

            if(book[left]+book[right] == target)

            {

                return "YES";

            }

            else if(book[left]+book[right] < target) left++;

            else right++;

        }

        return "NO";

    }

}