P12903 [HackerEarth] pair sums
普及
题目描述

You have been given an integer array A and a number K. Now, you need to find out whether any two different elements of the array A sum to the number K. Two elements are considered to be different if they lie at different positions in the array. If there exists such a pair of numbers, print "YES" (without quotes), else print "NO" without quotes.

Input Format:

The first line consists of two integers N, denoting the size of array A and K. The next line consists of N space separated integers denoting the elements of the array A.

Output Format:

Print the required answer on a single line.

Constraints:

1 ≤ N ≤ 10^6

1 ≤ K ≤ 2*10^6

1 ≤ A[i] ≤ 10^6

SAMPLE INPUT
5 9
1 2 3 4 5

SAMPLE OUTPUT
YES

Explanation

Here, A[4] + A[5] = 4 + 5 = 9. So, the answer is YES.

输入格式

见题面

输出格式

见题面

样例输入
5 9 1 2 3 4 5 SAMPLE
样例输出
YES