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.io.Source

object Main{
  def main(args: Array[String]){
    val line =
      for{
        in <- Source.stdin.getLines.toList
      } yield in.map(c => c.toLower)

      val filteredSting = line.mkString.map(_.toLower).filter(('a' to 'z').contains(_))
      println((filteredSting + ('a' to 'z').mkString).groupBy(n => n).toList.sorted.map{
        case (k,v) => s"$k : ${v.length - 1}"
      }.mkString("\n"))
  }
}