org 100h
Start:
        mov     ah, $09
        mov     dx, strHelloUser
        int     21h

Input:
        mov     ah, $0A
        mov     dx, bufInput
        int     21h

OutputBeforeChange:
        mov     ah, $09
        mov     dx, bufInput + 2
        int     21h

ProcessOnResult:
        mov     cl, [bufInput + 1]
        cmp     cl, 4
        jnge    OutputLenghtBad

        mov     al, [bufInput + 2 + 1]
        mov     bl, [bufInput + 3 + 1]
        cmp     al, bl
        jne     OutputNo

        mov     al, [bufInput + 3 + 1]
        cmp     al, 65
        jnge    OutputNo
        cmp     al, 90
        jnle    OutputNo

        xor     bh, bh
        mov     bl, [bufInput + 1]
        sub     bl, 2
        cmp     [bufInput + bx], 65
        jnge    OutputNo
        cmp     [bufInput + bx], 90
        jnle    OutputNo

OutputYes:
        mov     ah, $09
        mov     dx, strYes
        int     21h
        jmp     AvaitingClose

OutputNo:
        mov     ah, $09
        mov     dx, strNo
        int     21h
        jmp     AvaitingClose

OutputLenghtBad:
        mov     ah, $09
        mov     dx, strLenghtBad
        int     21h
        jmp     AvaitingClose

AvaitingClose:
        mov     ah, $09
        mov     dx, strClose
        int     21h

        mov     ah, $08
        int     21h
        ret

strHelloUser    db      'Please, enter your string:',13,10,36
bufInput        db      8, 0, 8 dup(7),13,10,36
strLenghtBad    db      'Lenght...',13,10,36
strNo           db      'Incorrect',13,10,36
strYes          db      'Correct',13,10,36
strClose        db      'Press any key to close programm... $'