N = int(input())
X = list(map(int,input().split(" ")))

a = set(sorted([abs(X[i] - X[i + 1]) for i in range(N) if i + 1 < N]))


if 0 in a: 
    a.remove(0)
    if sum(a) == 0:
        print(0)
    else:
        print(min(a))
else:
    print(min(a))