(define (iota n . args)
  (let ((start (if (pair? args) (car args) 0))
        (step  (if (and (pair? args) (pair? (cdr args))) (cadr args) 1)))
    (let loop ((m n) (last (+ start (* step (- n 1)))) (a '()))
      (if (zero? m)
          a
	  (loop (- m 1) (- last step) (cons last a))))))

(define (solve a)
  (let loop((b (sort a <)) (prev -1001001001) (res 1001001001))
    (if (null? b)
	(if (= res 1001001001) 0 res)
	(let ((curr (car b)))
	  (if (= curr prev)
	      (loop (cdr b) curr res)
	      (loop (cdr b) curr (min res (- curr prev))))))))

(display (solve (let ((N (read))) (map (lambda (x) (read)) (iota N)))))
(newline)