Input and sub - Microprocessor

.MODEL SMALL
.STACK 100H
.DATA
A DB 100
B DB 5
C DB 4
.CODE
MAIN PROC
    MOV AX,@DATA
    MOV DS,AX

    MOV AL,A
    MOV BL,B

    SUB AL,BL
    ;ADD AL,48

    MOV AH,2
    MOV DL,AL
    INT 21H

MAIN ENDP
END MAIN