# compute the area of a triangle
# (having its three sides)
# Let's transform the code

import math

a= []
for i range(3):
    a.append(float(input(f'Side { i + 1}:')))

s = sum(a) /2
area = math.sqrt(
    s * math.prod( #python 3.8
        map(
            lambda x: s - x, a
        )
    )
)

print(f'The area is {area}')

