#include <bits/stdc++.h>

using namespace std;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int x1,y1,x2,y2;
    cin>>x1>>y1>>x2>>y2;
    if(x1 == x2 && y1 != y2)
        cout<<2;
    else if(y1 == y2 && x1 != x2)
        cout<<2;
    else if(x2 - x1 != y2- y1)
        cout<<0;
    else if(x1 == y1 && x2 == y2)
        cout<<1;

}