ErasingCharacters.txt

PROBLEM STATEMENT
Fox Ciel received a string as a birthday present. However, the string was too long for her, so she decided to make it shorter by erasing some characters.


The erasing process will look as follows:

Find the smallest i such that the i-th character and the (i+1)-th character of the string are same.
If there is no such i, end the process.
Remove the i-th and the (i+1)-th character of the string, and repeat from 1.



For example, if she receives "cieeilll", she will change the string as follows: "cieeilll" -> "ciilll" -> "clll" -> "cl". You are given a string s. Return the string she will get after she erases characters as described above.

DEFINITION
Class:ErasingCharacters
Method:simulate
Parameters:string
Returns:string
Method signature:string simulate(string s)


CONSTRAINTS
-s will contain between 1 and 50 characters, inclusive.
-Each character in s will be a lowercase letter ('a'-'z').


EXAMPLES

0)
"cieeilll"

Returns: "cl"

This is the example from the statement.

1)
"topcoder"

Returns: "topcoder"

She won't erase any characters at all.

2)
"abcdefghijklmnopqrstuvwxyyxwvutsrqponmlkjihgfedcba"

Returns: ""



3)
"bacaabaccbaaccabbcabbacabcbba"

Returns: "bacbaca"



4)
"eel"

Returns: "l"