.MODEL SMALL
.STACK 100H

 .DATA
   PROMPT_1   DB  'Enter first letter : $'
   PROMPT_2   DB  'Enter second letter : $'
   PROMPT_3   DB  'Output : $'
   NEXT_LINE  DB  0DH,0AH,"$"

 .CODE
   MAIN PROC
     MOV AX, @DATA
     MOV DS, AX

     MOV AH, 2
     MOV DL, "?"
     INT 21H

     MOV AH, 9

     LEA DX, NEXT_LINE
     INT 21H

     LEA DX, PROMPT_1
     INT 21H

     MOV AH, 1
     INT 21H
     MOV BL, AL
     MOV AH, 9

     LEA DX, NEXT_LINE
     INT 21H

     LEA DX, PROMPT_2
     INT 21H

     MOV AH, 1
     INT 21H
     MOV BH, AL
     MOV AH, 9

     LEA DX, NEXT_LINE
     INT 21H

     LEA DX, PROMPT_3
     INT 21H

     MOV AH, 2

     CMP BL, BH

     JAE @GREATER
       MOV DL, BL
       INT 21H

       MOV DL, BH
       INT 21H

       JMP @END

@GREATER:
       MOV DL, BH
       INT 21H

       MOV DL, BL
       INT 21H
@END:

     MOV AH, 4CH
     INT 21H
   MAIN ENDP
 END MAIN