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 JAVA (judge verdict: Accepted)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		StringBuilder alphabet = new StringBuilder("abcdefghijklmnopqrstuvwxyz");
		String s = sc.nextLine();
		while(sc.hasNextLine()){
			s += sc.nextLine();
		}
		int[] ans = new int[26];
		int count;

		for(int i=0;i<alphabet.length();i++) {
			count = 0;
			for(int j=0;j<s.length();j++) {

				if(alphabet.substring(i, i+1).equalsIgnoreCase(s.substring(j,j+1))) {
					count++;
				}

			}
			ans[i] = count;
		}

		for(int i=0;i<ans.length;i++) {
			System.out.println(Character.toLowerCase(alphabet.charAt(i)) + " : " + ans[i]);
		}

		sc.close();
	}

}