python入门 --求一元二次方程的解

import math
a=float(raw_input('Input a:'))
b=float(raw_input('Input b:'))
c=float(raw_input('Input c:'))
if a!=0:
    delta=b**2-4*a*c
    if delta<0:
        print 'No solution'
    elif delta==0:
        s=-b/(2*a)
        print 's:',s
    else:
        root=math.sqrt(b**2-4*a*c);
        s1=(-b+root)/(2*a);
        s2=(-b-root)/(2*a);
        print 'The solution are:',s1,s2