#!/usr/bin/env gosh
(define (parse-input)
  (let ((n (read (open-input-string (read-line)))))
    (define (iter i acc)
      (if (= i 0)
          acc
          (let ((lst (read (open-input-string (string-append "(" (read-line) ")")))))
            (iter (- i 1) (cons lst acc)))))
    (iter n '())))

(define (nyanpass lst)
  (define (nyanpass-pos lst acc index)
    (if (null? lst)
        acc
        (if (or (eq? 'nyanpass (car lst))
                (eq? '- (car lst)))
            (nyanpass-pos (cdr lst) (cons index acc) (+ index 1))
            (nyanpass-pos (cdr lst) acc (+ index 1)))))
  (define (renchon? n lst)
    (if (null? lst)
        #t
        (if (and (not (eq? 'nyanpass (list-ref (car lst) n)))
                 (not (eq? '- (list-ref (car lst) n))))
            #f
            (renchon? n (cdr lst)))))
  (define (iter maybe-renchon acc)
    (if (null? maybe-renchon)
        acc
        (if (renchon? (car maybe-renchon) lst)
            (iter (cdr maybe-renchon)
                  (cons (+ (car maybe-renchon) 1)
                        acc))
            (iter (cdr maybe-renchon)
                  acc))))
  (iter (nyanpass-pos (car lst) '() 0) '()))

(let* ((ren-list (nyanpass (parse-input))))
  (if (= (length ren-list) 1)
      (display (car ren-list))
      (display -1))
  (newline))