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-----
2
3 1 4 1 5 9

-----Sample Output-----
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.

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