#include <iostream>
#include <cmath>

int main(){
  long double x,y,l;
  std::cin >> x;
  std::cin >> y;
  std::cin >> l;
  long long sum = 0;
  sum = std::ceil(std::abs(x)/l) + std::ceil(std::abs(y)/l);
  if(x != 0){
    sum++;
  }
  if(y < 0){
    if(x == 0) sum++;
    sum++;
  }
  std::cout << sum << std::endl;
}