#include <bits/stdc++.h>

using namespace std;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cerr.tie(0);

    int64_t x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;

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

    cout.flush();
    return 0;
}