a,b,c,d,e,f = map(int,input().split())
if a < 0:
    a,b,c,d,e,f = -a,-b,-c,-d,-e,-f
r2 = (f-e+(c**2)/(4*a)+(d**2)/(4*a))/a
r = r2**(1/2)
print(r)