D = {}
D['name'] = [1, 2, 5, 4, 2, 1, 6]
D['name_1'] = [1, 1, 1, 1]
D['name_2'] = [2, 1]
D['name_3'] = [1, 4]

def get_score(Dict):
  final_score = 0.
  mini_seq = 0
  for key_, list_ in Dict.items():
    cur_list = list_
    cur_list.sort()
    len_ = len(cur_list)

    if (len_ <= 1):
      mini_seq += 1
      continue

    new_list = [0] * len_
    cur_cl = -1
    cur_cnt = 0
    cur_ptr = -1
    for j in range(len_):
      if (j == 0):
        cur_cl = cur_list[j]
        cur_cnt = 1
        cur_ptr = 0
      else:
        if (cur_list[j] == cur_cl):
          cur_cnt += 1
        else:
          new_list[cur_ptr] = cur_cnt
          cur_cl = cur_list[j]
          cur_cnt = 1
          cur_ptr += 1
    new_list[cur_ptr] = cur_cnt

    cur_score = 0.

    for el in new_list:
      cur_score += (len_ - el)**2
    cur_score /= (len_ - 1) * len_ * len_

#     print(cur_score)

    final_score += cur_score

  if (len(Dict.keys()) == mini_seq):
    return 0.
  final_score /= (len(Dict.keys()) - mini_seq)
  return final_score

print(get_score(D))