output_description: Print the expected number of games that will be played, in the manner
  specified in the statement.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N A B C
attempt: n, a, b, c = (int(i) for i in input().split())
  a = a / 100
  b = b / 100
  
  
  def bitsu(n):
      r = 1
      for i in range(n):
          r = r * (i + 1)
      return r
  
  
  def comb(n, k):
      return bitsu(n) / (bitsu(k) * bitsu(n - k))
  
  
  def pos(a, b, k):  # k回目で終わる確率
      return (a**n) * (b ** (k - n)) * comb(n, k) + (a ** (k - n)) * (b**n) * comb(n, k)
  
  
  r = 0
  for i in (n, 2 * n - 1):
      r = r + i * pos(a, b, i)
  print(r)
  
problem_description: Statement
  
  Takahashi and Aoki will play a game. They will repeatedly play it until one of
  them have N wins in total.
  
  When they play the game once, Takahashi wins with probability A %, Aoki wins
  with probability B %, and the game ends in a draw (that is, nobody wins) with
  probability C %. Find the expected number of games that will be played, and
  print it as follows.
  
  We can represent the expected value as P/Q with coprime integers P and Q.
  Print the integer R between 0 and 10^9+6 (inclusive) such that R \times Q
  \equiv P\pmod {10^9+7}. (Such an integer R always uniquely exists under the
  constraints of this problem.)
samples: [{"input": "1 25 25 50", "output": "2\n    \n\nSince N=1, they will repeat the game until one of them wins. The expected\nnumber of games played is 2.\n\n* * *"}, {"input": "4 50 50 0", "output": "312500008\n    \n\nC may be 0.\n\n* * *"}, {"input": "1 100 0 0", "output": "1\n    \n\nB may also be 0.\n\n* * *"}, {"input": "100000 31 41 28", "output": "104136146"}]