Sells Submarines

[If you have any requirements, feel free to ask. I promise to do my best in order to fulfill your requests. However, we must be assured that you would not leak the three submarines voiceprint...]

According to the mail that Chen Fan had just received, the other side had obeyed, and in a somewhat less arrogant attitude than before. After pondering its contents for a long time, Chen Fan responded to the email.

[I assure you that we have a good reputation, which has been guarantees for decades. We never deceive customers and never cheat customers. So, you don't have to worry about the leaking problem. We promise that, if you find this three submarines voiceprint not to be completely leak-proof, we can provide you with a free hostile submarine voiceprint as compensation. We would then only have one request: six hundred million dollars! You must give me a reply within two days. Otherwise, the consequences will be very serious! ]