#!/usr/bin/python
from itertools import izip, tee
def pairwise(iterable):
    "s -> (s0,s1), (s1,s2), (s2,s3), ..."
    a, b = tee(iterable)
    next(b, None)
    return izip(a, b)

N = int(raw_input())
X = map(int, raw_input().split())
srt = sorted(set(X))
difs = [y-x for x, y in pairwise(srt)] or [0]
print min(difs)