#include <iostream>
using namespace std;

int main()
{
    int x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;
    if (x1 == x2 || y1 == y2) cout << 2 << "\n";
    else if (abs(x2 - x1) == abs(y2 - y1)) cout << 1 << "\n";
    else cout << 0 << "\n";
    return 0;
}