Problem Description

Xiao S wants to submit a wonderfully written solution on Luogu, but Xiao Q doesn't want to see Xiao S's solution getting more likes than her own. Therefore, she deliberately inserts some strange characters into Xiao S's solution.

Specifically, the original solution can be considered as a string \( S \) containing only lowercase or uppercase letters. Xiao Q inserts some random characters at several positions in \( S \), which could be numbers or punctuation marks, but definitely not letters, and are present on the keyboard. We call the string after the addition of these characters \( S' \).

Your task is to remove all non-alphabetical characters from \( S' \) and then output the resulting string.

Input Format

The input consists of a single line, a string \( S' \), representing the string after the addition of characters.

Output Format

The output consists of a single line, a string \( S \), representing the original string.

Sample Input and Output

Sample Input #1

`` I*Love*Luogu**333#$$ ``` ### Sample Output #1 ``` ILoveLuogu ``` ### Sample Input #2 ``` L2u4o6gu##$%Lov()es^me ``` ### Sample Output #2 ``` LuoguLovesme ``` ### Sample Input #3 ``` []{}->%_;'pxprpx ``` ### Sample Output #3 ``` pxprpx ``` ## Notes ### Sample 1 Explanation In the string `I*Love*Luogu**333#$$, characters *, #, $ are punctuation marks, and 3 is a digit. These are the added characters. After deletion, the string becomes ILoveLuogu.

Sample 2 Explanation

In the string L2u4o6gu##$%Lov()es^me`, characters `#`, `$, %, (, ), ^, \ are punctuation marks, and 2, 4, 6 are digits. These are the added characters. After deletion, the string becomes LuoguLovesme.

Data Range

For the first $30\%$ of the data, it is guaranteed that \( S' \) contains only Latin letters.
For the next $30\%$ of the data, it is guaranteed that \( S' \) contains only Latin letters and underscores _.
For $100\%$ of the data, it is guaranteed that the length of \( S' \) is between $1$ and $10^6$, and \( S' \) only contains letters, punctuation marks, and digits from the main keyboard area, excluding spaces, newline characters, and other end-of-line symbols.

见题面 Input 部分

见题面 Output 部分