#include <algorithm>
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define ll long long
#define INF 1000000000000000000

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N;
    cin >> N;
    deque<ll> A(2 * N);
    rep(i, 2 * N) { cin >> A[i]; }

    ll homura = 0, tenpura = 0;
    while (!A.empty()) {
        ll frdiff = A[0] - A[1];
        ll badiff = A[A.size() - 1] - A[A.size() - 2];
        if (frdiff > badiff) {
            homura += A[0];
            tenpura += A[1];
            A.pop_front();
            A.pop_front();
        } else {
            homura += A[A.size() - 1];
            tenpura += A[A.size() - 2];
            A.pop_back();
            A.pop_back();
        }
    }

    cout << homura - tenpura << endl;
}