运行以下代码，正确的打印结果是？（ ）

def f(s):

    t=0

    max=0

    for i in s:

        if i>="0" and i<="9":

            t=t+1

        else:

            if t>max:

                max=t

            t=0

    print(max)

list="123ab45cd6d"

f(list)