#coding:utf-8

from math import fabs

N=input()
X=map(int,raw_input().split())

X.sort()

s=[]
for i in range(N):
	if i==len(X)-1:
		break
	else:
		s.append(int(fabs(X[i]-X[i+1])))

s.sort()

if len(set(s))==1:
	print 0
else:	
	for i in s:
		if i!=0:
			print i
			break