07/11/07 12:45:46
>>69
#include<stdio.h>
int main(void){
int x,y,x1,y1,x2,y2;
printf("x1 y1 x2 y2 = ");
scanf("%d %d %d %d",&x1,&y1,&x2,&y2);
x=x1>x2?x1-x2:x2-x1;
y=y1>y2?y1-y2:y2-y1;
if(x==0&&y==0)printf("0");
else if(x==y)printf("1");
else if(x%2==y%2)printf("2");
else printf("-1");
printf("\n");
return 0;
}