text: 
  with open("input") as f:
      t, buses = f.read().strip().split("\n")
      t = int(t)
      buses = buses.split(',')
  
  first = map(int, filter(lambda x: x!='x', buses))
  a, b = min((x-t%x, x) for x in first)
  print(a*b)
  
  # https://en.wikipedia.org/wiki/Chinese_remainder_theorem
  
  
  
  