n = int(input())
xn = list(map(int,input().split()))
min_dis = 10000**2
flag = False
for i in range(0,len(xn)-1):
    for j in range(i+1,len(xn)):
        dis = abs(xn[i]-xn[j])
        if min_dis>dis and xn[i]!=xn[j]:
            min_dis = dis
            flag= True
if flag:
    print(min_dis)
else:
    print(0)