Problem Statement

In Python3 and PyPy3, the following code is sometimes written in code golf (the practice of getting AC with as short a code as possible).

print("YNeos"[x::2])

This code prints Yes when $x = 0$ and No when $x = 1$.

Let us consider whether a string like this YNeos can be applied to other output formats as well.

You are given strings $X, Y$ consisting of uppercase and lowercase English letters.

Determine whether there exists a string $S$ consisting of uppercase and lowercase English letters that satisfies the following conditions, and if it exists, print that $S$.
If it does not exist, print a $?$ mark (?).

• The string obtained by extracting the odd-positioned characters of $S$ and concatenating them in their original order is $X$.
• The string obtained by extracting the even-positioned characters of $S$ and concatenating them in their original order is $Y$.

Constraints

• $X, Y$ are strings consisting of uppercase and lowercase English letters
• $1 \leq |X|, |Y| \leq 100$ ($|X|, |Y|$ are the lengths of $X, Y$, respectively)

Input

The input is given from standard input in the following format.

$X$
$Y$

Output

If there exists an $S$ satisfying the conditions in the problem statement, print that $S$.
If it does not exist, print a $?$ mark (?).

Sample

Yes
No

YNeos

Takahashi
Aoki

?

Alice
Bruno

ABlriucneo