output_description: Print an integer representing the sum of the interior angles of a regular
  polygon with N sides.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: def gcd(a, b):
      if b == 0:
          return a
      else:
          return gcd(b, a % b)
  
  
  def opt(a, b):
      c = gcd(a, b)
      return a // c, b // c
  
  
  def dot(A, B):
      a = A[0] * B[0]
      b = A[1] * B[1]
      return opt(a, b)
  
  
  def add(A, B):
      return opt(A[0] * B[1] + B[0] * A[1], A[1] * B[1])
  
  
  N, A, B, C = map(int, input().split())
  
  A = opt(A, 100)
  B = opt(B, 100)
  C = opt(C, 100)
  
  g = 1000000007
  
  c = [((1, 1), 0, 0, 0)]
  ans = (0, 1)
  e = (0, 1)
  pi = 0
  while pi < len(c):
  
      PQ, cnt, acnt, bcnt = c[pi]
      pi += 1
  
      if e[1] > (e[1] - e[0]) * g * 100:
          continue
      if acnt >= N or bcnt >= N:
          e = add(e, PQ)
          ans = add(ans, opt(cnt * PQ[0], PQ[1]))
          continue
  
      cnt += 1
      c.append((dot(PQ, A), cnt, acnt + 1, bcnt))
      c.append((dot(PQ, B), cnt, acnt, bcnt + 1))
      c.append((dot(PQ, C), cnt, acnt, bcnt))
  
  
  print(ans[0] * pow(ans[1], g - 2, g) % g)
  
problem_description: Statement
  
  Given an integer N not less than 3, find the sum of the interior angles of a
  regular polygon with N sides.
  
  Print the answer in degrees, but do not print units.
samples: [{"input": "3", "output": "180\n    \n\nThe sum of the interior angles of a regular triangle is 180 degrees.\n\n* * *"}, {"input": "100", "output": "17640"}]