The first time I came into contact with Bitcoin was in 2011 when I was working at Levi's in Chongqing's Jiefangbei. At that time, there was a rather neutral female colleague named Tang Jiaqi. After work, I would go to an internet café to mine Bitcoin. One day, I was in the same class as her, and out of curiosity, I went to the internet café to mine with her after work. I knew nothing back then and eventually bought 10 from her. She sent the encrypted wallet file to my email, and later I went to Beijing to trade a bit, but didn't understand it and left it alone. If she still has that file, it would be worth 7 million at today's price, but only I know the password. The second time was in 2012 when I was working in Beijing, and I bought quite a few from colleagues. I remember the QT wallet only supported XP systems back then, so I specifically reinstalled the notebook's operating system. I should have around 50 BTC in memory. The wallet file was saved to 360 Cloud, and later my computer blue-screened, so I went to reinstall the system again. Naturally, I forgot it again. Later, 360 Cloud cleared user data. Around the same time, I also registered for a mobile app wallet; I only remember registering with my email and phone number, and it could back up to my email. It seems that I could also log in with a phone verification code. I could also print the QR code private key. I searched for a long time but couldn't find which wallet it was. In the end, I felt like it was a blockchain wallet, but when I contacted support, they said the email did not correspond to a wallet ID. I bought it three or four times, but I couldn't find any of them.