ribs(20-n4)

(define (ribs )                                                  ;
  (define in (open-input-file "matrix.txt"))                     ;
(define (iter lst i)
  (define line (read-line in))                                  ; Нумерация вершин с 1!!!
  (if (equal? line eof) lst
    (iter (append (help (string->list line) i 1 '()) lst) (+ i 1))))
  (iter '() 1))
(define (help lst Nstr i result)
  (cond
    ( (equal? #\return (car lst)) result)
    ( (> i Nstr) result)
    ( (equal? (car lst) #\1) (help (cdr lst) Nstr (+ i 1) (cons (cons Nstr i) result)))
    ( (equal? #\space (car lst)) (help (cdr lst) Nstr i result))
    (else (help (cdr lst) Nstr (+ i 1) result))))