add gopy function

Signed-off-by: tuyetphale993 <tuyetphale993@gmail.com>
Add phieu gop y function

Signed-off-by: tuyetphale993 <tuyetphale993@gmail.com>
 Fix Trasach function

Signed-off-by: tuyetphale993 <tuyetphale993@gmail.com>