#include <bits/stdc++.h>
using namespace std;
typedef long long  ll;
typedef vector<int> VI;
typedef vector<ll> VLL;
#define rep(i,n) for(int i=0; i<(int)(n); i++)

int main(){
    ll n,ans = 0,sum=0;
    cin >> n;
    VLL a(2*n);

    rep(i,2*n)cin >> a[i];

    ll l = 0, r = 2*n -1, ls = a[0]-a[1], rs = a[2*n-1] - a[2*n -2];

    while(sum != 2*n){
        if(ls > rs){
            ans += ls;
            l += 2;
            ls = a[l] - a[l+1];
            sum += 2;
        }else{
            ans += rs;
            r -= 2;
            rs = a[r] - a[r-1];
            sum += 2;
        }
    }

    cout << ans << endl;
}