# WAP to calculate area of the trangle

s1 = float(input("Enter the 1st side: "))
s2 = float(input("Enter the 2st side: "))
s3 = float(input("Enter the 3st side: "))

s = (s1 + s2 + s3)/2

area = (s *(s - s1) * (s - s2) * (s - s3)) * 0.5

print("\n",area)