Unique Common Elements

Given two lists of integers, your task is to find the common elements that appear exactly once in each list. In other words, a number is considered common if it appears exactly one time in the first list and exactly one time in the second list. You are not allowed to use built-in set operations. The order of the output numbers does not matter.

For example, if the first list is [1, 2, 3, 4, 5] and the second list is [4, 5, 6, 7, 8], then the output should be:

$$Output: 4\ 5$$

inputFormat

The input consists of two lines provided via standard input.

The first line contains space-separated integers representing the first list.
The second line contains space-separated integers representing the second list.

outputFormat

Output the common unique elements (i.e. numbers that appear exactly once in each list) as space-separated integers in a single line. If no such elements exist, print an empty line.## sample

1 2 3 4 5
4 5 6 7 8

4 5