Degree of second offence

Programming requirements

In the editor on the right Begin-End Supplementary code between , Calculate the whole number （ Not more than 100 position , The data is provided by the platform ） Make two and return . Specifically “ The degree of a second offense ” The definition is as follows ：

This number contains 2 The ratio of the number of bits to the number of bits ;
If the integer is negative , The degree increases 0.5 times ;
If the integer is even , Is to add 1 times .
Tips ： For the requirements of this customs, the calculation shall not exceed 100 An integer , Obviously, you can't use int type , But you can treat a string of numbers as a string , Use a character array to receive input integers .

for example ： Numbers -56782223456 It's a 11 digit , Among them is 3 individual 2, It's a negative number , And even , Then its offense degree is ：3/11×1.5×2, about 0.818182.

Test examples

Input ：-13142223336
Output ：0.818182

i=input()
if i[0] == "-":  
    b = i.count("2")/len(i[1:])  
    b*=1.5  
else:  
    b = i.count("2")/len(i)  
if int(i[-1])%2==0:  
    b*=2  
print("%.6f"%b)