Toph easy problem(Pie Are Squared)

Question:

Pie Are Squared

Limits: 1s, 512 MB

Given the radius of a circle, calculate and print its area.

The area of a circle can be computed using the following formula:

$A = \pi r^2$

Input

The input file will contain one floating point number r (r < 2000).

Output

Print the area of the circle (rounded to five decimal places).

Samples

Input	Output
2 Solve in C: #include<stdio.h> #define PI 3.141592653589793 int main() { int r; double A; scanf("%d",&r); A=PI*r*r; printf("%.10f",A); return 0; }	12.5663706144