# coding=utf-8

###
### for python program
###

import sys
import math

# math class
class mymath:
    ### pi
    pi = 3.14159265358979323846264338

    ### Prime Number
    def pnum_eratosthenes(self, n):
        ptable = [0 for i in range(n+1)]
        plist = []

        for i in range(2, n+1):
            if ptable[i]==0:
                plist.append(i)
                for j in range(i+i, n+1, i):
                    ptable[j] = 1
        return plist

    def pnum_check(self, n):
        if (n==1):
            return False
        elif (n==2):
            return True
        else:
            for x in range(2,n):
                if(n % x==0):
                    return False
            return True

    ### GCD
    def gcd(self, a, b):
        if b == 0:
            return a
        return self.gcd(b, a%b)

    ### LCM
    def lcm(self, a, b):
        return (a*b)//self.gcd(a,b)

    ### Mat Multiplication
    def mul(self, A, B):
        ans = []
        for a in A:
            c = 0
            for j, row in enumerate(a):
                c += row*B[j]
            ans.append(c)
        return ans
    
    ### intチェック
    def is_integer(self, n):
        try:
            float(n)
        except ValueError:
            return False
        else:
            return float(n).is_integer()

    ### 幾何学問題用
    def dist(self, A, B):
        d = 0
        for i in range(len(A)):
            d += (A[i]-B[i])**2            
        d = d**(1/2)
        return d

    ### 絶対値
    def abs(self, n):
        if n >= 0:
            return n
        else:
            return -n

mymath = mymath()

### output class
class output:
    ### list
    def list(self, l):
        l = list(l)
        #print(" ", end="")
        for i, num in enumerate(l):
            print(num, end="")
            if i != len(l)-1:
                print(" ", end="")
        print()

output = output()

### input sample
#i = input()
#N = int(input())
#A, B, C = [x for x in input().split()]
#N, K = [int(x) for x in input().split()]
#inlist = [int(w) for w in input().split()]

#R = float(input())
#A.append(list(map(int,input().split())))

#for line in sys.stdin.readlines():
#    x, y = [int(temp) for temp in line.split()]

#abc list
#abc = [chr(ord('a') + i) for i in range(26)]

### output sample
# print("{0} {1} {2:.5f}".format(A//B, A%B, A/B))
# print("{0:.6f} {1:.6f}".format(R*R*math.pi,R*2*math.pi))
# print(" {}".format(i), end="")

def printA(A):
    N = len(A)
    for i, n in enumerate(A):
        print(n, end='')
        if i != N-1:
            print(' ', end='')
    print()

# リスト内包表記 ifあり
# [x-k if x != 0 else x for x in C]

# ソート（代入する必要なし）
# N.sort()

# 10000個の素数リスト
# P = mymath.pnum_eratosthenes(105000)

def get_input():
    N = []
    while True:
        try:
            N.append(input())
            #N.append(int(input()))
            #N.append(float(input()))
        except EOFError:
            break
    return N

while True:
    N = int(input())
    if N==0:
        break
    A = [int(x) for x in input().split()]

    ans = 1145141919

    A.sort()

    for i in range(N-1):
        if ans > abs(A[i]-A[i+1]):
            ans = abs(A[i]-A[i+1])

    print(ans)



Measured memory_bytes: 5712