Delete more then ONE

//https://vk.com/evgenykravchenko0

                ___                                        ___                   ___
               /  /\                  ___                 /  /\                 /  /\
              /  /:/_                /__/\               /  /:/_               /  /:/_
             /  /:/ /\               \  \:\             /  /:/ /\             /  /:/ /\
            /  /:/ /:/_               \  \:\           /  /:/_/::\           /  /:/ /:/_
           /__/:/ /:/ /\          ___  \__\:\         /__/:/__\/\:\         /__/:/ /:/ /\
           \  \:\/:/ /:/         /__/\ |  |:|         \  \:\ /~~/:/         \  \:\/:/ /:/
            \  \::/ /:/          \  \:\|  |:|          \  \:\  /:/           \  \::/ /:/
             \  \:\/:/            \  \:\__|:|           \  \:\/:/             \  \:\/:/
              \  \::/              \__\::::/             \  \::/               \  \::/
               \__\/                   ~~~~               \__\/                 \__\/
                            ___
                           /__/\                ___                 ___
                           \  \:\              /  /\               /  /\
                            \  \:\            /  /:/              /  /:/
                        _____\__\:\          /__/::\             /__/::\
                       /__/::::::::\         \__\/\:\__          \__\/\:\__
                       \  \:\~~\~~\/            \  \:\/\            \  \:\/\
                        \  \:\  ~~~              \__\::/             \__\::/
                         \  \:\                  /__/:/              /__/:/
                          \  \:\                 \__\/               \__\/
                           \__\/

;##  DATA SEGMENT  ##
DATASEG Segment
    enter_str       db  'Enter string:$'
    invite          db  '> $'
    error_max       db  'more then one maximum letters$'
    error_bln       db  'blank string$'
    error_one       db  'one letter$'
    string          db  255, ?, 255 dup(?)
    letters         db  26 dup(0)
DATASEG Ends
;##  /DATA SEGMENT  ##




;##  STACK SEGMENT  ##
STACKSEG Segment Stack
    db 100h dup(?)
STACKSEG Ends
;##  /STACK SEGMENT  ##





;##  CODE SEGMENT  ##
CODESEG Segment
    Assume CS:CODESEG, DS:DATASEG, SS:STACKSEG

;##  Procedure`s And Macro`s  ##

;## Vyvod pustoi stroki ##
writeln macro
    push dx
    push ax
    mov ah,2
    mov dl,13
    int 21h
    mov dl,10
    int 21h
    pop ax
    pop dx
endm

;##  Vyvod stroki  ##
write macro string
    push ax
    push dx
    mov ah,09h
    mov dx,offset string
    int 21h
    pop dx
    pop ax
endm

;##  exit prog  ##
exit macro
    mov al,0
    mov ah,4Ch
    int 21h
endm

;##  Clear Screen  ##
clrscr macro
    push ax
    push bx
    push cx
    push dx
    mov ax,0600h
    mov bh,07h
    xor cx,cx
    mov dh,24
    mov dl,80
    int 10h
    mov ah,0fh
    int 10h
    mov dx,0101h
    mov ah,2
    int 10h
    pop dx
    pop cx
    pop bx
    pop ax
endm


;##  Readkey  ##
readkey macro registr
    push ax
    mov ah,10h
    int 16h
    mov registr,ax
    pop ax
endm


error_p_one:
    mov dx,offset error_one
    mov ah,09h
    int 21h
    jmp the_end
error_p_bln:
    mov dx,offset error_bln
    mov ah,09h
    int 21h
    jmp the_end

;##  /Procedure`s And Macro`s  ##

;##  Programm  ##
  start:
    mov ax,DATASEG
    mov ds,ax
;-------------
    clrscr
    write enter_str
    writeln
    write invite

    mov ah,0Ah
    mov dx,offset string
    int 21h

    writeln

    xor ch,ch
    mov bx,2
    mov cl,string[1]

    cmp cx,1
    je error_p_one

    cmp cx,0
    je error_p_bln

    xor ah,ah
find_repeat_letters:
    mov al,string[bx]
    inc bx
    cmp al,'a'
    jge low_registry
    sbb al,'A'
    inc al
    jmp skip_low_reg
    low_registry:
    sbb al,'a'
    skip_low_reg:
    mov si,ax
    inc letters[si]
    loop find_repeat_letters


;find max repeated letter

    xor di,di
put_number:
    mov ah,letters[di]
    inc di
    cmp ah,0
    je put_number

    dec di

    mov bx,1
    mov cx,26
find_max:
;   cmp bx,di
;   jne skip_dec
;       dec cx
;       inc bx
;   skip_dec:
    mov al,letters[bx]
;   cmp al,ah
;   je error_p_max
    cmp al,ah
    jl skip_mov
        mov ah,al
        mov di,bx
    skip_mov:
    inc bx
    loop find_max


    mov ah,letters[di]
    mov cx,26
    xor bx,bx
two_or_more_max:
    cmp bx,di
    jne skip_dec
        dec cx
        inc bx
    skip_dec:
    mov al,letters[bx]
    cmp al,ah
    je error_p_max
    inc bx
    loop two_or_more_max


    mov dx,di
    xchg dh,dl


    mov ah,02h
    mov bx,2
;   xor ch,ch
    mov cl,string[1]

print_new_string:
    mov dl,string[bx]
    inc bx
    add dh,'a'
    cmp dl,dh
    je skip_out
    sub dh,'a'
    add dh,'A'
    cmp dl,dh
    je skip_out
        int 21h
    skip_out:
    sub dh,'A'
    loop print_new_string
    jmp the_end

error_p_max:
    mov dx,offset error_max
    mov ah,09h
    int 21h


the_end:
    readkey ax
    writeln
quit:
    exit
CODESEG Ends
;##  /CODE Segment  ##
End start
;##  /Programm  ##