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)

#include <set>
#include <map>
#include <queue>
#include <ctime>
#include <cmath>
#include <cstdio>
#include <bitset>
#include <vector>
#include <cstring>
#include <cassert>
#include <iostream>
#include <algorithm>
using namespace std;
typedef double db;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int,int> pa;
typedef unsigned int uint;
typedef unsigned long long ull;
#define w1 first
#define ls (x<<1)
#define w2 second
#define ins insert
#define rs (x<<1|1) 
#define mp make_pair
#define pb push_back
#define mid ((l+r)>>1)
#define sqr(x) ((x)*(x))
#define cle(x) ((x).clear())
#define lowbit(x) ((x)&(-x))
#define SZ(x) (int((x).size()))
#define ms(x,y) memset(x,y,sizeof (x))
#define rep(i,a,b) for(int (i)=(a);(i)<=(b);(i)++)
#define rep2(i,a,b) for(int (i)=(a);(i)<(b);(i)++)
#define per(i,a,b) for(int (i)=(a);(i)>=(b);(i)--)
#define Rep(p,x) for(int (p)=head[(x)];(p);(p)=nxt[(p)]) 
#define Rep2(p,x) for(int (p)=cur[(x)];(p);(p)=nxt[(p)])
#define debegin printf("debug\nbegin\n")
#define deend printf("debug\nend\n")
#define isfind printf("find\n")
template<class T>inline void rread(T&num){
	num=0;T f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9')num=num*10+ch-'0',ch=getchar();
	num*=f;
}
inline int getgcd(int x,int y){if(!x)return y;return getgcd(y%x,x);}
inline int power(int x,int k,int p){int res=1;for(;k;k>>=1,x=(ll)x*x%p)if(k&1)res=(ll)res*x%p;return res;}
const double pi=acos(-1);
inline void judge(){
	freopen("input.txt","r",stdin);
} 
//********************************head*************************************	
const int maxn=3e5+5;
int n;
int a[maxn];
ll pre[maxn],suf[maxn];
ll ans=-1e18;
priority_queue<int,vector<int> >Small;
priority_queue<int,vector<int>,greater<int> >Big;
int main(){
	rread(n);
	rep(i,1,3*n)rread(a[i]);
	rep(i,1,3*n){
		pre[i]=pre[i-1];
		if(SZ(Big)<n)Big.push(a[i]),pre[i]+=a[i];
		else if(Big.top()<a[i])pre[i]-=Big.top(),Big.pop(),Big.push(a[i]),pre[i]+=a[i];
	}
	per(i,3*n,1){
		suf[i]=suf[i+1];
		if(SZ(Small)<n)Small.push(a[i]),suf[i]+=a[i];
		else if(Small.top()>a[i])suf[i]-=Small.top(),Small.pop(),Small.push(a[i]),suf[i]+=a[i];
	}
	rep(i,n,2*n)ans=max(ans,pre[i]-suf[i+1]);
	printf("%lld\n",ans);
	return 0;
}