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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <functional>
#include <utility>
#include <tuple>
#include <cctype>
using namespace std;
//#define INF 0x3f3f3f3f
#define INF 1100000000000000000LL
#define MOD 1000000007
#define mp make_pair
#define mt make_tuple
#define pb push_back
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pint;
typedef vector<int> vint;
typedef vector<ll> vll;
int dx[8]={0,0,-1,1,1,1,-1,-1};
int dy[8]={-1,1,0,0,1,-1,1,-1};
const int SIZE=100050;
//int arr[SIZE]={};
//ここまでテンプレ
signed main(){
	int N;
	cin>>N;
	vll a;
	for(int i=0;i<3*N;i++){
		ll c;
		cin>>c;
		a.pb(c);
	}
	priority_queue<ll,vector<ll>,greater<ll>> fro;
	priority_queue<ll> bac;
	ll fsum=0,bsum=0;
	for(int i=0;i<N;i++){
		fro.push(a[i]);
		fsum+=a[i];
	}
	for(int i=2*N;i<3*N;i++){
		bac.push(a[i]);
		bsum+=a[i];
	}
	ll f[3*SIZE]={},b[3*SIZE]={};
	f[N-1]=fsum,b[2*N]=bsum;
	for(int i=N;i<2*N;i++){
		fro.push(a[i]);
		fsum+=a[i];
		fsum-=fro.top();
		fro.pop();
		f[i]=fsum;
	}
	for(int i=2*N-1;i>=N;i--){
		bac.push(a[i]);
		bsum+=a[i];
		bsum-=bac.top();
		bac.pop();
		b[i]=bsum;
	}
	ll ans=-INF;
	for(int i=N-1;i<2*N;i++){
		ans=max(ans,f[i]-b[i+1]);
	}
	cout<<ans<<endl;
	return 0;
}