Background

Description

Given two strings, a and b, return the result of putting them together in the order abba, e.g. "Hi" and "Bye" returns "HiByeByeHi".

Format

Input

Output

Samples

Hi" "Bye

"HiByeByeHi"

Yo" "Alice

"YoAliceAliceYo"

What" "Up

"WhatUpUpWhat"

Limitation

1s, 1024KiB for each test case.