def main():
    N = int(input())
    X = list(map(int,input().split()))
    X = list(set(X))
    X.sort()
    if len(X) < 2:
        print('0')
    else:
        print(min(X[i+1]-X[i] for i in range(len(X)-1)))

if __name__ == '__main__':
    main()