permute A B C D A B C D A B D C A C B D A C D B A D C B A D B C B A C D B A D C B C A D B C D A B D C A B D A C C B A D C B D A C A B D C A D B C D A B C D B A D B C A D B A C D C B A D C A B D A C B D A B C