07. Area of Figures

from math import pi
figure = input()

if figure == 'square':
    a = float(input())
    area = a * a
    print(f"{area:.3f}")

if figure == 'rectangle':
    a = float(input())
    b = float(input())
    area = a * b
    print(f"{area:.3f}")

if figure == 'circle':
    a = float(input())
    area = a * a * pi
    print(f"{area:.3f}")

if figure == 'triangle':
    a = float(input())
    b = float(input())
    area = a * b / 2
    print(f"{area:.3f}")