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: import sys
  
  S = sys.stdin.read().lower()
  print("a:" + str(S.count("a" and "A")))
  print("b:" + str(S.count("b" and "B")))
  print("c:" + str(S.count("c" and "C")))
  print("d:" + str(S.count("d" and "D")))
  print("e:" + str(S.count("e" and "E")))
  print("f:" + str(S.count("f" and "F")))
  print("g:" + str(S.count("g" and "G")))
  print("h:" + str(S.count("h" and "H")))
  print("i:" + str(S.count("i" and "I")))
  print("j:" + str(S.count("j" and "J")))
  print("k:" + str(S.count("k" and "K")))
  print("l:" + str(S.count("l" and "L")))
  print("m:" + str(S.count("m" and "M")))
  print("n:" + str(S.count("n" and "N")))
  print("o:" + str(S.count("o" and "O")))
  print("p:" + str(S.count("p" and "P")))
  print("q:" + str(S.count("q" and "Q")))
  print("r:" + str(S.count("r" and "R")))
  print("s:" + str(S.count("s" and "S")))
  print("t:" + str(S.count("t" and "T")))
  print("u:" + str(S.count("u" and "U")))
  print("v:" + str(S.count("v" and "V")))
  print("w:" + str(S.count("w" and "W")))
  print("x:" + str(S.count("x" and "X")))
  print("y:" + str(S.count("y" and "Y")))
  print("z:" + str(S.count("z" and "Z")))
  
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"}]