def str2float(s: str): # 字符串转浮点数

    def fn(n,m): return n*10 + m

    def chrto(i): return ord(i) - ord('0');

    def xfn(n,m): return n/10 + m;

    def xchrto(i): return (ord(i) - ord('0'))/10;

    sary = s.split('.')

    return reduce(fn, map(chrto, sary[0])) + (0 if len(sary)==1 else reduce(xfn, map(xchrto, reversed(sary[1]))));