#include <stdio.h>
int itix,itiy,mokuhyoux,mokuhyouy,ans,zans;
int main(void) {
  printf("今の座標と目標の座標教えて:"); 
  scanf("%d  %d  %d  %d",&itix,&itiy,&mokuhyoux,&mokuhyouy);
if(itix<0){
  itix=itix*-1;
}
if(itiy<0){
  itiy=itiy*-1;
}
zans = mokuhyoux - itix + mokuhyouy - itiy;
if(zans < 4){
ans  = 1;

}

else{
ans = 2;
}
printf("%d\n",ans);
}