# -*- coding: utf8 -*-
import sys

for s in sys.stdin:
    s = s.strip()
    try:
        a = int(s)
        b = 0
        while a != 1:
            if a % 2== 0:
                a = a//2
            else:
                a = a*3+1
            b = b+1
        print(b)
    except EOFError:
        break

實測是這樣就過了:
s = s.strip()
if s == "":
    continue
可能測資中間會有空行吧

感恩 我AC了 以後有這種問題我會嘗試看看