#include <bits/stdc++.h>
#define ll long long
using namespace std;

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



    return 0;
}