#include <stdio.h>
#include <stdlib.h>

int main()
{
	int x1;
	int y1;
	int x2;
	int y2;
	scanf("%d %d", &x1, &y1);
	scanf("%d %d", &x2, &y2);
		if ((x1 == x2) || (y1 == y2))
		{
			printf("2");
		}
		else
		{
			if ((x2 - x1) == (y2 - y1))
			{
				printf("1");
			}
			else
			{
				printf("0");
			}
		}
}