What are the three ghosts saying?

Help. This is a funny topic about knowing words. In Chinese, three ghosts cannot form a Chinese character. The joke is: three stones are called Lei, three fires are called Yan, three people are called Zhong, three water are called Miao, and three trees are called Sen. So what are the names of the three ghosts? The answer is: help.

Extended information:

A little joke about knowing words: There was a scholar whose family was very poor. He thought about it and couldn't find the reason. One day, he looked at a locust tree in the courtyard and seemed to have some enlightenment: "There is a square yard with a tree growing in it. Isn't this the word "difficulty" for difficulty? No wonder I am so poor." He said. He called his son and asked him to cut down the tree quickly.

The son saw that the tree had deep roots and lush leaves, and he couldn't bear to cut it down, but he couldn't resist his father. When he raised the ax to chop, he suddenly had a plan in mind and hurriedly said to his father: "After cutting down the tree, we are still in the yard, wouldn't it become the word 'prison' for prisoners? That would be even more unlucky."

"Kun" and "Prison" are both ideographic words. "Kou" is composed of two pictographic radicals of "口" and "木". "口" means a wall and "木" means a tree. The whole character It means that trees are surrounded by walls and cannot stretch, which was later extended to mean poverty, difficulty, etc.; "prison" means that people are imprisoned in walls.

Reference: Baidu Encyclopedia - Ideological Characters