def char2num(sub):
    digits = {'0':0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9}
    return digits[sub]
def num2int(x,y):
    return x*10+y
def num2float(x,y):
    return x*0.1+y
dl = s.index('.')
intp,fltp = s[:dl],s[:dl:-1]
return reduce(num2int,map(char2num,intp))+reduce(num2float,map(char2num,fltp))*0.1