output_description: 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'_
input_description: A sentence in English is given in several lines.
attempt: """
  ITP-1_8-C
   ?????????????????????
  ?????????????????±??????????????????????????¢???????????????????????°?????°??????????????°????????????????????????????????? 
  ??????????°?????????¨??§??????????????\???????????????
  ???Input
  ?????°????????????????????????????????±???????????????????????????
  ???Output
  ?????????????????±???????????????????????¢???????????????????????°?????\??????????????¢?????§????????????????????????
  a : a????????°
  b : b????????°
  c : c????????°
    .
    .
  z : z????????°
  """
  
  # inputData
  # inputData = input()
  # cnt = [0]*26
  #
  # for i in range(len(inputData)):
  #     if "a" == inputData[i] or inputData[i] =="A":
  #         cnt[0] += 1
  #     elif "b" == inputData[i] or inputData[i] =="B":
  #         cnt[1] += 1
  #     elif "c" == inputData[i] or inputData[i] =="C":
  #         cnt[2] += 1
  #     elif "d" == inputData[i] or inputData[i] =="D":
  #         cnt[3] += 1
  #     elif "e" == inputData[i] or inputData[i] =="E":
  #         cnt[4] += 1
  #     elif "f" == inputData[i] or inputData[i] =="F":
  #         cnt[5] += 1
  #     elif "g" == inputData[i] or inputData[i] =="G":
  #         cnt[6] += 1
  #     elif "h" == inputData[i] or inputData[i] =="H":
  #         cnt[7] += 1
  #     elif "i" == inputData[i] or inputData[i] =="I":
  #         cnt[8] += 1
  #     elif "j" == inputData[i] or inputData[i] =="J":
  #         cnt[9] += 1
  #     elif "k" == inputData[i] or inputData[i] =="K":
  #         cnt[10] += 1
  #     elif "l" == inputData[i] or inputData[i] =="L":
  #         cnt[11] += 1
  #     elif "m" == inputData[i] or inputData[i] =="M":
  #         cnt[12] += 1
  #     elif "n" == inputData[i] or inputData[i] =="N":
  #         cnt[13] += 1
  #     elif "o" == inputData[i] or inputData[i] =="O":
  #         cnt[14] += 1
  #     elif "p" == inputData[i] or inputData[i] =="P":
  #         cnt[15] += 1
  #     elif "q" == inputData[i] or inputData[i] =="Q":
  #         cnt[16] += 1
  #     elif "r" == inputData[i] or inputData[i] =="R":
  #         cnt[17] += 1
  #     elif "s" == inputData[i] or inputData[i] =="S":
  #         cnt[18] += 1
  #     elif "t" == inputData[i] or inputData[i] =="T":
  #         cnt[19] += 1
  #     elif "u" == inputData[i] or inputData[i] =="U":
  #         cnt[20] += 1
  #     elif "v" == inputData[i] or inputData[i] =="V":
  #         cnt[21] += 1
  #     elif "w" == inputData[i] or inputData[i] =="W":
  #         cnt[22] += 1
  #     elif "x" == inputData[i] or inputData[i] =="X":
  #         cnt[23] += 1
  #     elif "y" == inputData[i] or inputData[i] =="Y":
  #         cnt[24] += 1
  #     elif "z" == inputData[i] or inputData[i] =="Z":
  #         cnt[25] += 1
  #
  # print ('a : %d' % (cnt[0]))
  # print ('b : %d' % (cnt[1]))
  # print ('c : %d' % (cnt[2]))
  # print ('d : %d' % (cnt[3]))
  # print ('e : %d' % (cnt[4]))
  # print ('f : %d' % (cnt[5]))
  # print ('g : %d' % (cnt[6]))
  # print ('h : %d' % (cnt[7]))
  # print ('i : %d' % (cnt[8]))
  # print ('j : %d' % (cnt[9]))
  # print ('k : %d' % (cnt[10]))
  # print ('l : %d' % (cnt[11]))
  # print ('m : %d' % (cnt[12]))
  # print ('n : %d' % (cnt[13]))
  # print ('o : %d' % (cnt[14]))
  # print ('p : %d' % (cnt[15]))
  # print ('q : %d' % (cnt[16]))
  # print ('r : %d' % (cnt[17]))
  # print ('s : %d' % (cnt[18]))
  # print ('t : %d' % (cnt[19]))
  # print ('u : %d' % (cnt[20]))
  # print ('v : %d' % (cnt[21]))
  # print ('w : %d' % (cnt[22]))
  # print ('x : %d' % (cnt[23]))
  # print ('y : %d' % (cnt[24]))
  # print ('z : %d' % (cnt[25]))
  
  import sys
  
  string = []
  for line in sys.stdin:
      string += line.lower()
  A = "abcdefghijklmnopqrstuvwxyz"
  for cnt0 in A:
      print(cnt0 + " : {}".format(string.count(cnt0)))
  
problem_description: Counting Characters
  
    
  
  Write a program which counts and reports the number of each alphabetical
  letter. Ignore the case of characters.
samples: [{"input": "This is a pen.", "output": "a : 1\n    b : 0\n    c : 0\n    d : 0\n    e : 1\n    f : 0\n    g : 0\n    h : 1\n    i : 2\n    j : 0\n    k : 0\n    l : 0\n    m : 0\n    n : 1\n    o : 0\n    p : 1\n    q : 0\n    r : 0\n    s : 2\n    t : 1\n    u : 0\n    v : 0\n    w : 0\n    x : 0\n    y : 0\n    z : 0"}]