Background

Description

Given two strings, append them together (known as "concatenation") and return the result. However, if the concatenation creates a double-char, then omit one of the chars, so "abc" and "cat" yields "abcat".

Format

Input

Output

Samples

abc" "cat

"abcat"

dog" "cat

"dogcat"

abc" "

"abc"

Limitation

1s, 1024KiB for each test case.