#include <bits/stdc++.h>
using namespace std;
int main()
{
int x1,x2,y1,y2;
while(cin>>x1>>y1>>x2>>y2)
{
if(x1==0 && y1==0 && x2==0 && y2==0)
break;
if(x1==x2 and y1==y2) printf("0\n");
else if( x1==x2 ||y1==y2|| abs(y1-y2)==abs(x1-x2)) printf("1\n");
else if ( abs(y1-y2)!=abs(x1-x2)) printf("2\n");
}
return 0;
}
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