#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
#define ll long long

int main()
{
	ll 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";
	return 0;
}