text: ##input
  # 3800000 5 108
  ##answer
  # 43766
  
  def binary_search(P, R, L, xmin, xmax):
    if xmax <= xmin:
      return None
  
    x = (xmax + xmin) / 2
  
    newP = P
    for i in range(0, L):
      temp = (x - (newP * (R/12/100)))
      newP -= temp
  
    if newP < -1e-7:
      return binary_search(P, R, L, xmin, x)
    elif newP > 1e-7:
      return binary_search(P, R, L, x, xmax)
    else:
      return x
  
  def main():
    (P, R, L) = (int(x) for x in input().split())
  
    M = binary_search(P, R, L, 0, P/2)
    print(round(M))
  
  if __name__ == '__main__':
      main()
  