String Concatenation

Background

In the world of programming, string operations are fundamental and common tasks. Congcong has recently been learning how to concatenate two strings and has encountered some special cases.

Problem Description

Given two strings, append them together (known as "concatenation") and return the result. However, if the concatenation creates a double-character (i.e., the last character of the first string is the same as the first character of the second string), then omit one of the characters. For example, concatenating "abc" and "cat" yields "abcat".

Input Format

Input is given from standard input in the following format.

S1 S2

Where $S1$ and $S2$ are two strings, separated by a single space. $S2$ can be an empty string.

Output Format

Output is printed to standard output in the following format.

Result

Where $Result$ is the concatenated string.

Sample

abc cat

abcat

dog cat

dogcat

abc 

abc

Sample Explanation

Sample 1: The first string is "abc\