In a country's cemetery, there are many epitaphs of heads of state. An epitaph in a corner reads:

When I was young, I had a great wish to change the world, but as I grew older, I found that I couldn't, so I wanted to change the whole country; But when I get older, I find that I don't have the ability to change my country, so I think my wish is to change my family; When I was old, I found that I was unable to change my family, so I thought I would change myself. When I was about to die, I found that I still hadn't changed myself. At this time, I thought, if my initial wish is to change myself, then if I change myself, it is also possible to change my family, my country and even the whole world.