What kind of joke is two shits explaining GDP? thank you

A and B saw a piece of shit on the road. A said, "If you can eat that thing, I'll give it to you100000." B saw such a good thing in the world, rose up and swallowed it, and B got100000. But with the aggravation of nausea, the more I think about it, the less interesting it is. I saw another shit when I was walking, so B said, "I dare to eat that shit. Do you dare to eat this shit? " If you eat it, I will give you back 654.38+0 million! "A thought about it and felt unwilling to spend100000 in vain, so she rose up to be a hero and ate that shit for100000. Both of them are too sick to walk. A said, why do you think we make such a big joke when we walk? I didn't get anything, but I ate two pieces of shit for nothing! B suddenly had a brainwave: we don't eat for free, we have created 20 million GDP!