Calculate the size of a table space that can be shrunk

1 SelectA.file#,a.name,a.bytes/1024x768/1024x768CURRENTMB,2Ceil (HWM*A.block_size)/1024x768/1024x768Resizeto,3(a.bytes-HWM*A.block_size)/1024x768/1024x768Releasemb,4        'ALTER DATABASE datafile" "||A.name||" "Resize'||5Ceil (HWM*A.block_size/1024x768/1024x768)|| 'M;'Resizecmd6  fromV$datafile A,7(Select file_id,Max(block_id+Blocks-1) HWM8         fromdba_extents e9        where exists(Select 1  fromDba_data_filesTen                              whereTablespace_name='lmps_users_201307'  and file_id=E.file_id) One        Group  by file_id) b A whereA.file#=B.file_id(+) -  and(a.bytes-HWM*Block_size)>0 - Order  by 5

Calculate the size of a table space that can be shrunk