num = STDIN.readlines.map(&:chomp)
X = num[0].to_i
Y = num[1].to_i
L = num[2].to_i
x = X.abs
y = Y.abs

count = 0
if Y > 0
  y_ans = Y.divmod(L)
  count += y_ans[0]
  if y_ans[1] > 0
    count += 1
  end
  count += 1 unless x == 0
  x_ans = x.divmod(L)
  count += x_ans[0]
  if x_ans[1] > 0
    count += 1
  end
  puts count
else
  count += 1
  x_ans = x.divmod(L)
  count += x_ans[0]
  if x_ans[1] > 0
    count += 1
  end
  count += 1 unless y == 0
  y_ans = y.divmod(L)
  count += y_ans[0]
  if y_ans[1] > 0
    count += 1
  end
  puts count
end