Let you help the boatman the way to carry dog, cat & mouse over river. If there is not boatman, the dog will bit cat, cat bit mouse. You'll help father, mother, 2 sons, 2 daughters, police & robber to over river. If there is not police, robber'll hit every body. If there is not father, the son will snivel mother. If there is not mother, the daughter'll snivel father.