output_description: Print an integer representing the minimum number of minutes needed to make N
  pieces of takoyaki.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N X T
attempt: import sys
  
  
  def input():
      return sys.stdin.readline().strip()
  
  
  def list2d(a, b, c):
      return [[c] * b for i in range(a)]
  
  
  def list3d(a, b, c, d):
      return [[[d] * c for j in range(b)] for i in range(a)]
  
  
  def list4d(a, b, c, d, e):
      return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
  
  
  def ceil(x, y=1):
      return int(-(-x // y))
  
  
  def INT():
      return int(input())
  
  
  def MAP():
      return map(int, input().split())
  
  
  def LIST(N=None):
      return list(MAP()) if N is None else [INT() for i in range(N)]
  
  
  def Yes():
      print("Yes")
  
  
  def No():
      print("No")
  
  
  def YES():
      print("YES")
  
  
  def NO():
      print("NO")
  
  
  sys.setrecursionlimit(10**9)
  INF = 10**19
  MOD = 10**19 + 7
  EPS = 10**-10
  
  N, X, T = MAP()
  
  ans = ceil(N, X) * T
  print(ans)
  
problem_description: Statement
  
  Takahashi loves takoyaki - a ball-shaped snack.
  
  With a takoyaki machine, he can make at most X pieces of takoyaki at a time,
  taking T minutes regardless of the number of pieces to make.
  
  How long does it take to make N takoyaki?
samples: [{"input": "20 12 6", "output": "12\n    \n\nHe can make 12 pieces of takoyaki in the first 6 minutes and 8 more in the\nnext 6 minutes, so he can make 20 in a total of 12 minutes.\n\nNote that being able to make 12 in 6 minutes does not mean he can make 2 in 1\nminute.\n\n* * *"}, {"input": "1000 1 1000", "output": "1000000\n    \n\nIt seems to take a long time to make this kind of takoyaki."}]