#include <iostream>
#include <iomanip>
#include <vector>
#include <utility>
#include <map>
#include <algorithm>
#include <queue>
#include <cmath>
#include <numeric>
#include <set>

using namespace std;
struct aaa{aaa(){cin.tie(nullptr); ios::sync_with_stdio(false); cout<<fixed<<setprecision(20);};}aaa;
template <class T>ostream &operator<<(ostream &o,const vector<T>&v){o<<"{";for(int i=0;i<(int)v.size();i++)o<<(i>0?", ":"")<<v[i];o<<"}";return o;}
#define debug(v) {cerr<<"\033[1;36m[debug]\033[m "<<#v<<" : "<<v<<endl;}

using int64 = long long;

int main() {
    int64 n;
    cin >> n;
    vector<int64> a(2*n);
    for (int64 i=0; i<2*n; i++) cin >> a[i];

    int64 ans1 = a[0] - a[1];
    int64 l = 2;
    int64 r = 2*n - 1;
    while(l < r) {
        if (a[l]-a[l+1] > a[r]-a[r-1]) {
            ans1 += a[l] - a[l+1];
            l+=2;
        } else {
            ans1 += a[r] - a[r-1];
            r-=2;
        }
    }

    int64 ans2 = a[2*n-1] - a[2*n-2];
    l = 0;
    r = 2*n - 3;
    while(l < r) {
        if (a[l]-a[l+1] > a[r]-a[r-1]) {
            ans2 += a[l] - a[l+1];
            l+=2;
        } else {
            ans2 += a[r] - a[r-1];
            r-=2;
        }
    }


    debug(ans1);
    debug(ans2);
    cout << max(ans1,ans2) << endl;
}