#include <iostream>
#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n,x1,x2,y1,y2;
    cin>>x1>>y1>>x2>>y2;
    if((x1==x2)||(y1==y2))
        n=2;
    else if(abs(x1-x2)==abs(y1-y2))
        n=1;
    else n=0;
    cout <<n<< endl;
    return 0;
}