#include<stdio.h>

      int main()

      {

        double r,ca,sa,cases,caseno=0;

        scanf("%d",&cases);

          while(cases--)

          {

            scanf("lf%",%r);

            sa=4*r*r;

            ca=2*acos(0.0)*r*r;

            printf("Case %lf: %lf",++caseno,sa-ca);

          }

        return 0;

      }