SOLUTION OF URI 1002

//     question of uri  1002 Area of a Circle
//1002  (Mahmud_Jamil)  BRUR




#include<stdio.h>
int main()
{
    double R,pi,A;
    scanf("%lf",&R);
    pi=3.14159;
    A=pi*R*R;
    printf("A=%.4lf\n",A);
    return 0;
}