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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#define _USE_MATH_DEFINES
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <limits.h>
#define EPS 1e-10
#define sq(n) ((n)*(n))
#define rep(i,n) for(i=0;i<n;i++)
#define rev(i,n) for(i=n-1;i>=0;i--)
#define sort(a,n) qsort(a,n,sizeof(TYPE),cmp)
#define sort_r(a,n) qsort(a,n,sizeof(TYPE),cmp_r);
#define chsort(s,n) qsort(s,n,sizeof(char),cmp)
#define chsort_r(s,n) qsort(s,n,sizeof(char),char_cmp_r);
#define TYPE long long
#define MEMSET(a) memset(a,0,sizeof(a))
long long mod=(long long)1e09+7;
int inf=1<<30;
long long llinf=1ll<<60;

int in(void){
    int i;scanf("%d",&i);
    return i;
}
long long llin(void){
    long long i;scanf("%lld",&i);
    return i;
}
double din(void){
    double i;scanf("%lf",&i);
    return i;
}
void chin(char s[]){
    scanf("%s",s);
}
void print(int a){
    printf("%d\n",a);
}
void llprint(long long a){
    printf("%lld\n",a);
}
void dprint(double a){
    printf("%.10f\n",a);
}
void print2(int a,int b){
    printf("%d %d\n",a,b);
}
long long max(long long a,long long b){
    return a>b?a:b;
}
long long min(long long a,long long b){
    return a<b?a:b;
}
int cmp(const void *a,const void *b){
    return *(TYPE *)a-*(TYPE *)b;
}
int cmp_r(const void *a,const void *b){
    return *(TYPE *)b-*(TYPE *)a;
}
int char_cmp(const void *a,const void *b){
    return strcmp((char *)a,(char *)b);
}
int char_cmp_r(const void *a,const void *b){
    return strcmp((char *)b,(char *)a);
}
void swap(int *a,int *b){
    int t=*a;
    *a=*b;
    *b=t;
}
long long gcd(long long x,long long y){
    return x%y?gcd(y,x%y):y;
}
long long lcm(long long x,long long y){
    return x/gcd(x,y)*y;
}

// write codes below this
// when you use 'sort',
// make sure TYPE macro is correct
long long a[300000],b[150000],c[150000];

int main(void){
    long long n=in(),i,j,sb=0,sc=0,ans;
    rep(i,3*n)a[i]=llin();
    rep(i,3*n/2)b[i]=a[i];
    for(j=0;i<3*n;i++,j++)c[j]=a[i];
    sort_r(b,3*n/2);
    sort(c,3*n-3*n/2);
    rep(i,n)sb+=b[i];
    rep(i,n)sc+=c[i];
    ans=sb-sc;
    if(n%2){
        b[3*n/2]=c[0];
        c[0]=llinf;
        sort_r(b,3*n/2+1);
        sort(c,3*n-3*n/2-1);
        sb=sc=0;
        rep(i,n)sb+=b[i];
        rep(i,n)sc+=c[i];
        ans=max(ans,sb-sc);
    }
    llprint(ans);
    return 0;
}