Description

Given a non-decreasing integer sequence $a_1, a_2, \dots, a_{n-1}, a_n$ and an integer $x$, determine whether there exist two numbers in the sequence whose sum equals $x$. If such a pair exists, output <span>”YES”</span>; otherwise, output <span>”NO”</span>.

Input Format

There are multiple test cases. For each test case:

• The first line contains two integers, $n$ and $x$ (where $n$ and $x$ are both less than 100,000), representing the number of elements in the integer sequence and the target sum $x$, respectively.
• The second line contains $n$ integers, $a_1$ to $a_n$, separated by spaces. The sequence satisfies $1 \leq a_1 \leq a_2 \leq \dots \leq a_{n-1} \leq a_n < 2^{31}$.
• The input ends with 0.

Output Format

For each test case, output a single line containing either <span>YES</span> or <span>NO</span>.

5 10
1 2 3 4 5
6 12
1 3 5 7 9 11
0 0

NO
YES

## Source

CodesOnline