N = int(raw_input())
A = map(int, raw_input().split())

# TLE解

MAX = 10 ** 7

mn = MAX
for i in xrange(N):
    for j in xrange(i + 1, N):
        v = abs(A[i] - A[j])
        if v > 0:
            mn = min(mn, v)

if mn == MAX:
    print 0
else:
    print mn