Problem:
Counting Characters

Write a program which counts and reports the number of each alphabetical letter. Ignore the case of characters.

Input

A sentence in English is given in several lines.

Output

Prints the number of alphabetical letters in the following format:

a : The number of 'a'
b : The number of 'b'
c : The number of 'c'
.
.
z : The number of 'z'

Constraints

The number of characters in the sentence < 1200

Sample Input

This is a pen.

Sample Output

a : 1
b : 0
c : 0
d : 0
e : 1
f : 0
g : 0
h : 1
i : 2
j : 0
k : 0
l : 0
m : 0
n : 1
o : 0
p : 1
q : 0
r : 0
s : 2
t : 1
u : 0
v : 0
w : 0
x : 0
y : 0
z : 0

Solution in Scala (judge verdict: Accepted)

import scala.collection.mutable
import scala.io.Source.stdin

object Main extends App {

  val lines = stdin.getLines()
  val xs = {
    val nums = ('a' to 'z').map { (_, 0) }

    val m = mutable.Map(nums: _*)
    for {
      line <- lines
      c    <- line.map { _.toLower }
      if c.isLetter && c <= 'z'
    } {
      m(c) += 1
    }
    m.toSeq.sorted
  }

  for ((k, v) <- xs) {
    println(s"$k : $v")
  }
}