#include <bits/stdc++.h>

using namespace std;

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

    if(x1 == x2 || y1 == y2)
        cout << 2 << endl;
    else if(abs(x1-x2) == abs(y1-y2))
        cout << 1 << endl;
    else
        cout << 0;

    return 0;
}