#include <iostream>

using namespace std;

bool iscorner(int x, int y) {
  return (x==0||x==2024) && (y==0||y==2024);
}
int main() {
  int xa, ya, xb, yb;
  cin >> xa >> ya >> xb >> yb;
  cout << (2 - iscorner(xa, ya) - iscorner(xb, yb)) << "\n";
}