output_description: Print the number of the subsequences such that all characters are different,
  modulo 10^9+7.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      S
attempt: import numpy as np
  
  n = int(input())
  s = list(input())
  
  count = []
  for i in range(26):
      count.append(1)
  
  for i in s:
      if i == "a":
          count[0] = count[0] + 1
      elif i == "b":
          count[1] = count[1] + 1
      elif i == "c":
          count[2] = count[2] + 1
      elif i == "d":
          count[3] = count[3] + 1
      elif i == "e":
          count[4] = count[4] + 1
      elif i == "f":
          count[5] = count[5] + 1
      elif i == "g":
          count[6] = count[6] + 1
      elif i == "h":
          count[7] = count[7] + 1
      elif i == "i":
          count[8] = count[8] + 1
      elif i == "j":
          count[9] = count[9] + 1
      elif i == "k":
          count[10] = count[10] + 1
      elif i == "l":
          count[11] = count[11] + 1
      elif i == "m":
          count[12] = count[12] + 1
      elif i == "n":
          count[13] = count[13] + 1
      elif i == "o":
          count[14] = count[14] + 1
      elif i == "p":
          count[15] = count[15] + 1
      elif i == "q":
          count[16] = count[16] + 1
      elif i == "r":
          count[17] = count[17] + 1
      elif i == "s":
          count[18] = count[18] + 1
      elif i == "t":
          count[19] = count[19] + 1
      elif i == "u":
          count[20] = count[20] + 1
      elif i == "v":
          count[21] = count[21] + 1
      elif i == "w":
          count[22] = count[22] + 1
      elif i == "x":
          count[23] = count[23] + 1
      elif i == "y":
          count[24] = count[24] + 1
      elif i == "z":
          count[25] = count[25] + 1
  
  print((np.prod(count) - 1) % (10**9 + 7))
  
problem_description: Statement
  
  You are given a string S of length N. Among its subsequences, count the ones
  such that all characters are different, modulo 10^9+7. Two subsequences are
  considered different if their characters come from different positions in the
  string, even if they are the same as strings.
  
  Here, a subsequence of a string is a concatenation of **one or more**
  characters from the string without changing the order.
samples: [{"input": "4\n    abcd", "output": "15\n    \n\nSince all characters in S itself are different, all its subsequences satisfy\nthe condition.\n\n* * *"}, {"input": "3\n    baa", "output": "5\n    \n\nThe answer is five: `b`, two occurrences of `a`, two occurrences of `ba`. Note\nthat we do not count `baa`, since it contains two `a`s.\n\n* * *"}, {"input": "5\n    abcab", "output": "17"}]