Problem:
Score : 500 points

Problem Statement

Let N be a positive integer.

There is a numerical sequence of length 3N, a = (a_1, a_2, ..., a_{3N}).
Snuke is constructing a new sequence of length 2N, a', by removing exactly N elements from a without changing the order of the remaining elements.
Here, the score of a' is defined as follows: (the sum of the elements in the first half of a') - (the sum of the elements in the second half of a').

Find the maximum possible score of a'.

Constraints

1 ≤ N ≤ 10^5

a_i is an integer.

1 ≤ a_i ≤ 10^9

Partial Score

In the test set worth 300 points, N ≤ 1000.

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_{3N}

Output

Print the maximum possible score of a'.

Sample Input 1

2
3 1 4 1 5 9

Sample Output 1

1

When a_2 and a_6 are removed, a' will be (3, 4, 1, 5), which has a score of (3 + 4) - (1 + 5) = 1.

Sample Input 2

1
1 2 3

Sample Output 2

-1

For example, when a_1 are removed, a' will be (2, 3), which has a score of 2 - 3 = -1.

Sample Input 3

3
8 2 2 7 4 6 5 3 8

Sample Output 3

5

For example, when a_2, a_3 and a_9 are removed, a' will be (8, 7, 4, 6, 5, 3), which has a score of (8 + 7 + 4) - (6 + 5 + 3) = 5.

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

N = int(input())
array=[int(n) for n in input().split()]
lst=[]
for i in range(N):
    a =len(array)//2 -1
    l=array[:a+1]
    r= array[a+1:]
    if max(r)-array[a] > array[a]- min(l) > 0 or max(r)-array[a] > 0 > array[a]- min(l):
        r.pop(r.index(max(r)))
        array= l+r
    elif  array[a]- min(l) >max(r)-array[a] > 0 or  array[a]- min(l) > 0 > max(r)-array[a]:
        l.pop(l.index(min(l)))
        array= l+r
    else:
        array.remove(array[a])
print(sum(array[:N])-sum(array[N:]))