#include<bits/stdc++.h>
using namespace std;
int main()
{
    double x1,y1,x2,y2;
    cin>>x1>>y1;
    cin>>x2>>y2;
    if(x1==x2 && y1==y2)
    {
        cout<<0<<endl;
        return 0;
    }
    if(x1==x2 || y1==y2)
    {
        cout<<2<<endl;
        return 0;
    }
    if(abs(x1-x2)==abs(y1-y2))
    {
        cout<<1<<endl;
        return 0;
    }
    else
    {
        cout<<0<<endl;
        return 0;
    }
    
}