The emperor asked the two generations to buy him a kind of "three things to eat" fruit, otherwise he would be beheaded. How did he get it?

One day, two generations of love walked into the street and saw an old man with a heavy heart. Then go forward and ask. The old man told the emperor of two generations to buy food for three days. If he couldn't, he would be beheaded. How do two generations want to help the elderly? He finally came up with an idea and said to the old man, "buy a watermelon!" " ""Is that all right? " The old man asked, pulling two generations of love together to see the emperor. When he got there, the emperor asked, "Did you bring anything to eat?" Two generations put watermelon in front of the emperor unhurriedly, saying, "This is food that can be eaten three times." The emperor said angrily, "You dare to coax me with watermelon, don't you?" The old man trembled at the emperor's words. The two generations said to the emperor unhurriedly, "Watermelon skin can be fried, meat can be eaten raw, and seeds can be given to chickens." "Excuse me, isn't this a three-course dish?" The emperor suddenly realized and said, "I am not as good as you!" " Finally, the emperor invited two generations to be his teachers.