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

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

    if (x1 != x2 && y1 != y2)
    {
        if ((abs(x2 - x1)) == (abs(y2 - y1))) cout << "1" << endl;
        else cout << "0" << endl;
    }
    else cout << "2" << endl;

    return 0;
}