(define (birler sayi) 
        (item sayi '(bir iki uc dort bes alti yedi sekiz dokuz)))

(define (onlar sayi)
        (item sayi '(on yirmi otuz kirk elli altmis yetmis seksen doksan)))

    ;the function for-4dec convert the number into 4 decimal number
(define (for-4dec sayi)
       (cond ((< (count sayi) 4)(word ((repeated bl (count sayi)) "0000") sayi))
             (else sayi)))

(define (binler-bas sayi)(cond ((= sayi 1) 'bin) ((= sayi 0) 'yok)                                       (else (word (birler sayi) 'bin))))

(define (yuzler-bas sayi)(cond ((= sayi 1) 'yuz) ((= sayi 0) 'yok)                                       (else (word (birler sayi) 'yuz))))

(define (onlar-bas sayi)(cond ((= sayi 0) 'yok) (else (onlar sayi))))

(define (birler-bas sayi)(cond ((= sayi 0) 'yok) (else (birler sayi))))

(define (olmayan? wr)(not (equal? wr 'yok)))

;In the function secim ,keep olmayan? selects the decimals which are not equal  to 'yok ,since 'yok denotes the decimals which have 0 value 
(define (secim sent)(accumulate word (keep olmayan? sent)))

(define (convert num)
(cond ((not (integer? num))  "The argument is not an integer") 
      ((or (>= num 10000)(< num 0))                                                  "In school we have not seen yet how to express this")
      ((= (for-4dec num) '0000) 'sifir) 
(else (secim   
 (se (binler-bas (item 1 (for-4dec  num))) (yuzler-bas (item 2 (for-4dec num)))
 (onlar-bas (item 3 (for-4dec num))) (birler-bas (item 4 (for-4dec num))))))))