#include <stdio.h>
#include <iostream>
#include <cstdlib>
using namespace std;

int main()
{
    int x1,x2,y1,y2;
    cin>>x1;
    cin>>y1;
    cin>>x2;
    cin>>y2;


   if(x1 == x2 || y1==y2)
    {
        cout<<2;
    }
   else
    {
        if(abs(x1-x2)== abs(y1-y2))
        {
         cout<<1;
        }
        else cout<<0;
    }
}