def main():
  data = sys.stdin.readlines()
  numbers = data.split()
  x = 0
  y = 0

  for i in range (0, len(numbers)):
    numbers[i] = int(numbers[i])

    if (numbers[0] % numbers[2] != 0):
    x = (numbers[0] / numbers[2]) + 1
    else:
    x = numbers[0] / numbers[2]

    if(numbers[1] % numbers[2] != 0):
      y = (numbers[1] / numbers[2]) + 1
    else:
      y = numbers[1] / numbers[2]
    sys.stdout = x * y