n = int(input())
x = list(map(int,input().split()))
dif = []
x.sort()

for i in range(n-1):
    dif.append(x[i+1] - x[i])

dif.sort()
if dif[0] == 0 and dif[-1] == 0:
    ans = 0
else:
    for i in dif:
        if i != 0:
            ans = i
            break

print(ans)