Three people laugh at themselves when they meet savages.

The savage who rowed for the first time crossed the river with a man, and the savage came back; The second time the savage crossed the river with the savage, the savage who could row came back; The third time the savage crossed the river with a man, the savage who could row came back; The fourth time, you can take any barbarian or man. The savage who can row will come back, and for the fifth time, everyone will cross the river together.