#include <iostream>
#include <cmath>

using namespace std;

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