include 'emu8086.inc'
.model small
.stack 100h
.data
a db ?
.code
main proc

    mov ah,1
    int 21h
    mov bl,al

    cmp bl,"a"
    jge d1
    cmp bl,"A"
    jge d3
    d3:
    cmp bl,"Z"
    je print
    cmp bl,"Z"
    jl d4
    d4:
    mov ah,2
    mov dl,0ah
    int 21h
    mov dl,0dh
    int 21h
    add bl,33
    mov dl,bl
    mov ah,2
    int 21h
    jmp exit
    d1:
    cmp bl,"z"
    je print
    cmp bl,"z"
    jl d2
    d2:
    mov ah,2
    mov dl,0ah
    int 21h
    mov dl,0dh
    int 21h
    sub bl,31
    mov dl,bl
    mov ah,2
    int 21h
    jmp exit

    print:

    mov ah,2
    mov dl,0ah
    int 21h
    mov dl,0dh
    int 21h

    printn "ok"
    jmp exit

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

end main