Introduction to Blue Bridge Cup 1. Area of circle

Problem: Given the radius r of the circle, find the area of ​​the circle.
Input format The
input contains an integer r, which represents the radius of the circle.
Output format
Output one line, including a real number, rounded to 7 digits after the decimal point, indicating the area of ​​the circle.

import math
r = int(input())
S= math.pi*r*r
print('%.7f'%S)

7
153.9380400