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>
#include <ctype.h>

int main(void) {
  char input;
  int counts[26] = {};
  int i;
  while (1) {
    scanf(" %c", &input);
    if (input == '.')
      break;
    if (isalpha(input)) {
      if (isupper(input))
	counts[tolower(input) - 'a']++;
      else
	counts[input - 'a']++;
    }
  }
  for (i = 0; i < 26; i++)
    printf("%c : %d\n", i + 'a', counts[i]);
  return 0;
}