# Arup Guha
# 3/17/2025
# Solution to 2025 HSPT Problem: Apartment Subletting

# Get input and min side.
sides = [int(x) for x in input().split()]
small = min(sides)

# Using formula for triangle area .5absinC, and similar triangles, we see
# that we want to multiply each side by 1/sqrt(2) to get half the area.
print(small/(2**.5))