#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    long x1,x2,y1,y2;
    int brk = 0;
    cin>>x1>>y1;
    cin>>x2>>y2;

    if(abs(x1-x2) == abs(y1-y2))
        {
            brk = 1;  
        }
    if((x1==x2) or (y1==y2))
    {
        brk = 2;
    }
    std::cout << brk << std::endl;
    return 0;
}