Group Words by Length

You are given a list of words. The task is to group these words based on their length. For each unique word length \( L \) (where \( L = len(word) \)), output all the words having that length, preserving their input order. The groups should be printed in increasing order of \( L \).

Note: If the list is empty, no output should be produced.

Example:

Input:
6
apple
banana
pear
kiwi
grape
Cherry
Output:
4: pear, kiwi
5: apple, grape
6: banana, Cherry

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inputFormat

The first line of input contains a single integer \( n \), representing the number of words. The next \( n \) lines each contain a single word.

outputFormat

For each unique word length, output a single line in the format:

L: word1, word2, ...

where \( L \) is the word length. The groups must be printed in increasing order of \( L \). If there are no words, output nothing.

## sample

6
apple
banana
pear
kiwi
grape
Cherry

4: pear, kiwi
5: apple, grape
6: banana, Cherry

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