Exam

Emil stayed up late playing chess with Hussein before the exam, and now he's having trouble solving a problem. Can you help him out?

You are given two integers, k and l. Your task is to find two integers, a and b, such that:

• a + b = k

• a - b = l

If no such integers a and b exist, you should output "X".

Input

The input consists of a single line containing two integers k and l (-10^{18} ≤ k, l ≤ 10^{18}).

Output

Print a line with the integers a and b separated by a space, which satisfy the conditions above. If there are no such integers, print "X".

Examples