N = input()
Xs = map(int, raw_input().split())

if N < 2:
    ans = 0

else:
    Xs = sorted(set(Xs))
    ans = max(Xs)
    for i in range(len(Xs)-1):
        length = Xs[i+1] - Xs[i]
        if ans > length:
            ans = length

print ans