#include<iostream>
#include<cstdlib>
using namespace std;
int main()
{
	int x1, y1, x2, y2;
	scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
	if(x1==x2||y1==y2) printf("2");
	else if(x1-x2==y1-y2) printf("1");
	     else printf("0");
	return 0;
}