Assemble Subtraction Key Board Input

.MODEL SMALL
.STACK 100H

.CODE
MAIN PROC
    MOV AH, 1
    INT 21H             ;INPUT ONE
    MOV BL, AL


    MOV AH, 2
    MOV DL, 10    ; NEW LINE
    INT 21H

    MOV DL, 13
    INT 21H           ; BACK SPACE/CRET

    MOV AH, 1
    INT 21H             ;INPUT TWO
    MOV CL, AL

    SUB BL,CL
    ADD BL, 48 ;reduce when use big input as like 100 whose are greater than 9

    MOV AH, 2
    MOV DL, 10    ; NEW LINE
    INT 21H

    MOV DL, 13
    INT 21H           ; BACK SPACE/CRET

    MOV AH, 2
    MOV DL, BL
    INT 21H

MAIN ENDP
END MAIN