Chen was extremely hungry, so he left work and went to a local snack bar where he bought a cake. When Chen had eaten the cake, he found that he was still famished, and so he ate a second one.
Even then he was not full up and promptly ate six cakes in succession, but he hadn't satisfied his hunger. Not until Chen had eaten the seventh cake did he feel satisfied.
Then, suddenly, he had a feeling of regret. 'Ah, if I had known this before, I would have eaten the seventh cake first and that would have been enough and there would not have been any need to eat those six others.'. Thanks Sport-Guys