#include <bits/stdc++.h>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);(i)++)
#define rrep(i,x) for(int i=((int)(x)-1);i>=0;i--)
using namespace std;
using ll = long long;
using Int = long long;

const int MOD = 1000000007;
const ll INF = numeric_limits<ll>::max();
const int inf = 1e8;

//少数点表示
//cout <<std::fixed << std::setprecision(14)

int main(){
    cin.tie( 0 ); ios::sync_with_stdio( false );
    int n;
    cin >> n;
    vector<ll> a(n*2);
    rep(i,2*n) cin >> a[i];

    int r=(2*n)-1,l=0;
    ll ans=0;
    while(r-l>0){
        if(a[l]-a[l+1]>a[r]-a[r-1]){
            ans+=a[l]-a[l+1];
            l+=2;
        }else{
            ans+=a[r]-a[r-1];
            r-=2;
        }
    }

    cout << ans <<endl;


}