#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i=0; i<(n); ++i)
#define REP(i, d, n) for(int i=(d); i<(n); ++i)
#define all(v) v.begin(), v.end()
using ll = long long;
using P = pair<int, int>;

int main() {

    int n;
    cin >> n;
    vector<ll> a(2*n);
    rep(i, 2*n){
        cin >> a[i];
    }

    int right = 0, left = 2*n-1;
    ll homura = 0, tempra = 0;     
    rep(i, n){
        if(a[right] - a[right+1] > a[left] - a[left-1]){
            homura += a[right];
            tempra += a[right+1];
            right += 2;
        }
        else{
            homura += a[left];
            tempra += a[left-1];
            left -= 2;
        }
    }
    cout << homura - tempra << endl;

    return 0;
}