Pair with Given Sum

Given an array of N integers and a target integer K, determine if there exist two distinct elements a_i and a_j in the array such that their sum is exactly K. In other words, find if there exist indices i < j satisfying

$$a_i + a_j = K$$

If such a pair exists, output YES; otherwise, output NO.

Your solution should read input from standard input (stdin) and print the result to standard output (stdout).

inputFormat

The input consists of two lines:

• The first line contains two integers N and K, where N is the number of elements in the array and K is the target sum.
• The second line contains N space-separated integers representing the elements of the array.

outputFormat

Output a single line containing YES if there exists a pair of distinct elements whose sum is equal to K, and NO otherwise.

5 9
2 7 11 15 3

YES