学号：4201370
f = open('作业二素材.txt',encoding='utf-8')
txt = f.read()
f.close()
txt
index = txt.find('\n顺丰控股股份有限公司')
txt_target = txt[:index]
txt_target
a = txt_target.rfind('。')
b = txt_target[:a].rfind('。')
last_jz = txt_target[b+1:a+1]
last_jz
last_jz = last_jz.replace('\n','')
last_jz
print(len(last_jz))