answer: #Person1# and #Person2# find out there are no non-sleeping bullet train tickets from Shanghai to Beijing left. They will book plane tickets instead.
documents: #Person1#: Mike, shall we book two tickets online?
  #Person2#: Fine. Shanghai and Beijing are thousands of miles away. How about bullet train? Faster and relatively cheap, I think.
  #Person1#: Yeah. How many tickets remain?
  #Person2#: Oh, what a shame. Only sleeping cars have tickets. Others are all out of stock. The price of the sleeping car is almost the same as the airplane. You see, the discount plane tickets are no more than 500 yuan. A good deal, isn't it?
  #Person1#: Brilliant idea! That will make our journey rewarding and much safer.