#include <iostream>
#include <utility>
#include <memory>
#include <cmath>
using coord = std::pair<int, int>;

#ifndef BOOST_TEST_MAIN
int main(int const argc, char const** argv){
  int x, y, x2, y2;
  std::cin >> x >> y;
  std::cin >> x2 >> y2;
  coord dest = {x, y};
  coord king = {0, 0};
  auto p = std::make_shared<int>(king.first);
  auto q = std::make_shared<int>(king.second);

  double kdtilt = (double)y / (double)x; 
  double kotilt = (double)y2 / (double)x2;
  double kdlen = y * y + x * x;
  double kolen = y2 * y2 + x2 * x2;
  // std::cout << " kdtilt:" << kdtilt << " kdlen:" << kdlen << "\n";
  // std::cout << " kotilt:" << kotilt << " kolen:" << kolen << "\n";
    
  auto count = 0;

  // ナナメ一直線のときは1回ロス
  auto tiltcond = (kdtilt == kotilt == 1.0) || (kdtilt == kotilt == -1.0);
  if(tiltcond && kdlen > kolen){
    ++count;
  }
  
  for(; king != dest; ++count){
    // std::cout << * p << " " << * q << "\n";
    bool xisbigger = *p > dest.first;
    bool yisbigger = *q > dest.second;
    bool xissmaller = *p < dest.first;
    bool yissmaller = *q < dest.second;
    bool xeq = *p == dest.first;
    bool yeq = *q == dest.second;
    
    if(xeq && yeq){
      break;
    }
    
    if(xisbigger){
      -- *p;
      if(yisbigger){
	-- *q;
      }else if (yissmaller){
	++ *q;
      }
      continue;	
    }
    
    if(xissmaller){
      ++ *p;
      if(yisbigger){
	-- *q;
      }else if (yissmaller){
	++ *q;
      }
      continue;	
    }
    if(xeq){
      if(yisbigger){
	-- *q;
      }else if (yissmaller){
	++ *q;
      }
      continue;      
    }
  }
  std::cout << count;
}
#endif