Group by First Letter

Lab Python Intermediate 20 points

Read a line of words. Group them by their first letter and print each group as letter: word word, letters in alphabetical order, words in input order.

Input

One line.

Output

One line per letter.

Example

Input

apple bat avocado cat banana

Output

a: apple avocado
b: bat banana
c: cat

Sample input available Sample output available

Editor

Python

Hints

setdefault(key, []) returns the list for key, creating it first if needed.

Solution explanation

Grouping into lists inside a dict is a very common pattern. collections.defaultdict(list) is another way.

Show solution

groups = {}
for w in input().split():
    groups.setdefault(w[0], []).append(w)
for letter in sorted(groups):
    print(f"{letter}: {' '.join(groups[letter])}")

Output

Answer