Which button in pressed in Assembly?

.MODEL SMALL
.STACK 200H
.DATA
 MSG DB 0DH,0AH,'YOU PRESSED: '
 CHAR DB ?,'$'
.CODE
MAIN PROC

 MOV AX,@DATA
 MOV DS,AX
 
 MOV AH,1
 
 INT 21H
 MOV CHAR,AL
 
 LEA DX,MSG
 MOV AH,9
 INT 21H
 
 MOV AH,4CH
 INT 21H
 
 MAIN ENDP
END MAIN