#include <stdio.h>
#include <math.h>
#define PI 3.14
struct Elipse{
	int a;
	int b;
}Data={5,2};
struct coordinate{
	int x;
	int y;
	int z;
};
          
int main(void) {
	printf("area:%lf\n",PI*Data.a*Data.b);
	
	struct coordinate a={1,5,2};
    struct coordinate b={5,3,1};
	struct coordinate c={2,8,4};
	double length_ab;
	double length_co;
	length_ab=sqrt((b.x-a.x)*(b.x-a.x)+(b.y-a.y)*(b.y-a.y)+(b.z-a.z)*(b.z-a.z));
	length_co=sqrt(c.x*c.x+c.y*c.y+c.z*c.z);
	if(length_ab>length_co){
		printf("length:%lf\n",length_ab);
	}
		else 	{printf("length:%lf\n",length_co);
	}
	return 0;
}