.model small
.stack 100h
.data
s1 db "Enter Your Uppercase Letter $"
s2 db 10,13,"Lowercase Letter is: $"
t1 db 10,13,"Enter Your Lowercase Letter $"
t2 db 10,13,"Uppercase Letter is: $"
.code

main proc
    mov ax,@data
    mov ds,ax


    mov ah,9
    lea dx,s1
    int 21h

    mov ah,1
    int 21h
    mov bl,al
    add bl,32

    mov ah,9
    lea dx,t1
    int 21h

    mov ah,1
    int 21h
    mov cl,al
    sub cl,32


    mov ah,9
    lea dx,s2
    int 21h

    mov ah,2
    mov dl,bl
    int 21h

    mov ah,9
    lea dx,t2
    int 21h

    mov ah,2
    mov dl,cl
    int 21h

    exit:
    mov ah,4ch
    int 21h
    main endp
end main