import math
hen = list(map(float, raw_input().split()))
hens = sorted(hen)

if hens[0] == hens[1]:
	mins = math.sqrt(hens[1]*hens[1] + hens[0]*hens[0])
else:
	mins = math.sqrt(hens[1]*hens[1] - hens[0]*hens[0])
print mins