#include <bits/stdc++.h>
using namespace std;

int N;
vector<long long> A;
map<pair<int,int>, long long> memo;

long long f(int l, int r) {
    if (l >= r) return 0;
    auto key = make_pair(l, r);
    if (memo.count(key)) return memo[key];

    long long res = max(
        A[l] - A[l + 1] + f(l + 2, r),
        A[r] - A[r - 1] + f(l, r - 2)
    );

    memo[key] = res;
    return res;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N;
    A.resize(2 * N);
    for (int i = 0; i < 2 * N; i++) cin >> A[i];

    cout << f(0, 2 * N - 1) << "\n";
    return 0;
}