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

typedef long long ll;
#define pii pair<ll , ll>
#define _FastIO ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define MAXX  200005


ll max(ll a, ll b){
    if(a > b) return a;
    return b;
}

multiset<ll> ms;
multiset<ll>::iterator it;

ll s , n;
int a , b;
ll c[MAXX];

int main()
{
    _FastIO;
    cin >> n;
    for(ll i = 0; i < 2 * n; i++){
        cin >> a >> b;
        s += min(a , b); //putalarin minumlari topladiq
        ms.insert(a - b);//ferqlerini sortlayiriq multisetle time low az
    }
    ll y = 0; //saygac
    for(it = ms.begin(); it != ms.end(); it++){
        c[y] = *it;
        y++;
    }
    for(ll i = 0; i < n; i++){
        s += max(0 , (-1 * c[i])); // axsam yeyirik min top ucun en azi sifir yeye bilerik yoxsa a - b ucun -1 * c[i] tersi b cixiriq
    }
    for(ll i = n; i < 2 * n; i++){
        s += max(0 , c[i]);//seher yeyirik a - b a uste gelirik 1 * c[i] musbet
    }
    // s += max(0 , nese) onsuda s azalasi deyil cunki hamisin min cemi
    cout << s << endl;
    return 0;
}