Sum Pairs

We define a sum pair as a pair of numbers (a) and (b) from a given list such that (a+b=s), where (s) is a target sum. Given a list of integers and a target sum (s), your task is to find the first pair (in the order they appear) that satisfies this equation. If no such pair exists, output None.

inputFormat

Input is read from standard input. The first line contains a list of space-separated integers. The second line contains a single integer (s), the target sum.

outputFormat

If a valid pair is found, output the two numbers separated by a space. Otherwise, output None.## sample

1 4 8 7 3 15
8

1 7