digits = {'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9}
def char2num(str):
    return digits[str]
def fn(x,y):
    return x*10+y
num = s.split('.')
return reduce(fn,map(char2num,num[0]))+float(reduce(fn,map(char2num,num[1]))/(pow(10,len(num[1]))))