two letters display alphabetic order

.MODEL SMALL
.STACK 100H
.DATA
.CODE

MAIN PROC
    MOV AH,1
    INT 21H

    MOV BL,AL

    MOV AH,2
    MOV DL,0DH
    INT 21H

    MOV DL,0AH
    INT 21H


    MOV AH,1
    INT 21H

    MOV BH,AL

    MOV AH,2
    MOV DL,0DH
    INT 21H

    MOV DL,0AH
    INT 21H

    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