C :

# include <stdio.h>
#define p 3.1415
int main()
{
	float r,s,l;
	while(scanf("%f",&r)!=EOF)
	{
		printf("%.2f %.2f\n",2*r*p,r*r*p);
	}
	return 0;
} 

C++ :

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>
int main()
{
  //  freopen("in","r",stdin);
  //  freopen("out","w",stdout);

    float a;

    while(scanf("%f",&a)!=EOF)
    {


       printf("%.2f %.2f\n",3.1415*2*a,3.1415*a*a);
    }
  return 0;
}