Pair Sum Problem

You are given an array of n integers and a target sum k. Your task is to determine whether there exists a pair of distinct elements in the array whose sum is exactly equal to k. If such a pair exists, print YES; otherwise, print NO.

Formally, given an array \(a\) with \(n\) elements, check if there exist indices \(i\) and \(j\) (with \(i \neq j\)) such that \(a_i + a_j = k\).

inputFormat

The input is read from stdin and consists of two lines. The first line contains two integers: (n) (the number of elements in the array) and (k) (the target sum). The second line contains (n) integers representing the elements of the array.

outputFormat

Output a single line to stdout containing YES if there exists at least one pair of distinct elements that add up to (k), or NO otherwise.## sample

5 9
2 7 11 15 3

YES