diff --git a/src/SUDOKU.MID b/src/SUDOKU.MID
index 9f57746..df9743d 100644
--- a/src/SUDOKU.MID
+++ b/src/SUDOKU.MID
@@ -102,7 +102,8 @@ PUTLN:  PUSHJ P,OUTSTR                 ;Calls the OUTSTR subroutine
 
 ;Subroutine that reads the contents of the file into the buffer at FIELD
 IMPRTF: .CALL [SETZ ? SIXBIT/OPEN/
-                 [.UAI,,CHDSKI] ? A ? B ((SETZ))]
+            [.UAI,,CHDSKI] ? [SIXBIT/DSK]  ;Mode, channel and device name
+                A ? B ((SETZ))]
          .LOSE %LSFIL                  ;Handle errors after opening the file
         .CALL [SETZ ? SIXBIT/SIOT/
                 [,,CHDSKI] ? [BPTR,,C] ? [,,33] ((SETZ))]