import math
a,b,c=map(int,raw_input().split())
if not (a or b): print 0 if c else -1
elif not a:print '%.6lf'%(-c/1./b)
else:
  d=b*b-4*a*c
  if d<0:
    print 0
  else:
    k=2 if d else 1
    d=math.sqrt(d)
    r=[(-d-b)/2./a,(d-b)/2./a]
    print k
    for i in range(k):print '%.8lf'%r[i]