How do you beat the Japanese river game

1. Policeman and thief >
2. < Policemen
3. Policemen and son >
4. < Policemen and thief
5. father and son >
6. < father
7. father and mother >
8. < mother
9. policeman and thief >
10. < father
11. father and mother >
12. < mother
13. mother and daughter >
14. < policeman and thief
15. policeman and daughter >
16. < policemen
17. policeman and thief >