Area of Figures

import math

figure = input()

if figure == "square":
   a = float(input())
   area = a * a
   print(f"{area:.3f}")
elif figure == "rectangle":
    b = float(input())
    hb = float(input())
    area2 = b*hb
    print(f"{area2:.3f}")
elif figure == "circle":
    r = float(input())
    area3 = math.pi * r**2
    print(f"{area3:.3f}")
elif figure == "triangle":
    m = float(input())
    n = float(input())
    area4 = (m * n)/2
    print(f"{area4:.3f}")