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 C (judge verdict: Time Limit Exceeded)

#include <stdio.h>

int main(void) {
  int num,i;
  char ch;
  int counter[26];

  for(i = 0; i < 26; i++){
    counter[i] = 0;
  }

  while ( ch != EOF){
    scanf("%c",&ch);
    num = ch - 'a';  // 文字 ch の番号
    counter[num]++;
  }
  for(i = 0; i < 26; i++){
    ch = i + 'a';
    printf("%c : %d\n",ch,counter[i]);
  }
  return 0;
}