#include <iostream>
#include <vector>
#include <cmath>

using std::cout;
using std::cin;
using std::endl;

void conutInstruction(int a, int b, int c)
{
  int count;
  if ( a == 0 && b >= 0 )
    count = 0;
  else
    count = 1;
  
  // move to x axis direction
  count += fabs(b / c);
  if ( b % c !=0 )
    count++;
  //move to y axis direction
  count += fabs(a / c);
  if ( a % c != 0 )
    count++;
  //think the signature
  if ( b < 0 )
    count++;
  
  cout << count << endl;
}

int main(void)
{
  int x,y,z;
  cin >> x >> y >> z;
  conutInstruction(x, y, z);
  return 0;
}