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: # 全然賢いやり方あるはず
  (a, b, c, d, e, f, g, h, i_i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z) = (
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
      0,
  )
  while True:
      try:
          string = list(input())
      except:
          break
      for i in string:
          if i == "a" or i == "A":
              a += 1
          elif i == "b" or i == "B":
              b += 1
          elif i == "c" or i == "C":
              c += 1
          elif i == "d" or i == "D":
              d += 1
          elif i == "e" or i == "E":
              e += 1
          elif i == "f" or i == "F":
              f += 1
          elif i == "g" or i == "G":
              g += 1
          elif i == "h" or i == "H":
              h += 1
          elif i == "i" or i == "I":
              i_i += 1
          elif i == "j" or i == "J":
              j += 1
          elif i == "k" or i == "K":
              k += 1
          elif i == "l" or i == "L":
              l += 1
          elif i == "m" or i == "M":
              m += 1
          elif i == "n" or i == "N":
              n += 1
          elif i == "o" or i == "O":
              o += 1
          elif i == "p" or i == "P":
              p += 1
          elif i == "q" or i == "Q":
              q += 1
          elif i == "r" or i == "R":
              r += 1
          elif i == "s" or i == "S":
              s += 1
          elif i == "t" or i == "T":
              t += 1
          elif i == "u" or i == "U":
              u += 1
          elif i == "v" or i == "V":
              v += 1
          elif i == "w" or i == "W":
              w += 1
          elif i == "x" or i == "X":
              x += 1
          elif i == "y" or i == "Y":
              y += 1
          elif i == "z" or i == "Z":
              z += 1
  
  print("a : " + str(a))
  print("b : " + str(b))
  print("c : " + str(c))
  print("d : " + str(d))
  print("e : " + str(e))
  print("f : " + str(f))
  print("g : " + str(g))
  print("h : " + str(h))
  print("i : " + str(i_i))
  print("j : " + str(j))
  print("k : " + str(k))
  print("l : " + str(l))
  print("m : " + str(m))
  print("n : " + str(n))
  print("o : " + str(o))
  print("p : " + str(p))
  print("q : " + str(q))
  print("r : " + str(r))
  print("s : " + str(s))
  print("t : " + str(t))
  print("u : " + str(u))
  print("v : " + str(v))
  print("w : " + str(w))
  print("x : " + str(x))
  print("y : " + str(y))
  print("z : " + str(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"}]