Subtract Two Number

.MODEL SMALL
.STACK 100H
.DATA
.CODE

MSG1 DB "Enter 1st Number : $"
MSG2 DB "Enter 2nd Number : $"
MSG3 DB "Output is : $"
NEWLINE DB 0AH,0DH,"$"

MAIN PROC

    MOV AX,@DATA
    MOV DS,AX


    LEA DX,MSG1
    MOV AH,9
    INT 21H

    MOV AH,1
    INT 21H

    MOV BH,AL

    LEA DX,NEWLINE
    MOV AH,9
    INT 21H

    LEA DX,MSG2
    MOV AH,9
    INT 21H

    MOV AH,1
    INT 21H

    MOV BL,AL

    LEA DX,NEWLINE
    MOV AH,9
    INT 21H

    LEA DX,MSG3
    MOV AH,9
    INT 21H

    SUB BH,BL
    ADD BH,48

    MOV DL,BH

    MOV AH,2
    INT 21H

    MAIN ENDP
END MAIN