# yukicoder No.135 とりあえず1次元の問題

N = int(input())
X = [int(x) for x in input().split()]
M = 10 ** 6
min_d = M + 1

X.sort()

for i in range(N):
    if i > 0:
        d = X[i] - X[i - 1]

        if d > 0:
            min_d = min(d, min_d)

print(min_d if min_d <= M else 0)