Input (grade 13): Vietnamese general Tran Hung Dao sinks the entire fleet of an invading army of the Yuan Dynasty, by placing steel-tipped bamboo stakes in the Bach Dang River, near Halong Bay.
Output (grade 12): Vietnamese general Tran Hung Dao sinks the entire fleet of an invading Yuan dynasty Mongol army by placing steel-tipped bamboo stakes in the Bach Dang River, near Halong Bay.