#define  _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<cmath>
#include<stdio.h>
#include<cstdio>
#include<math.h>
#include<stdlib.h>
#include<string.h>
#include<string>
#include<algorithm>
#include<vector>
#include<stack>
#include<queue>
#include<deque>
#include<bitset>
#include<set>
#include<map>
#include<fstream>
#include<iomanip>
#include<climits>
#include<list>
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
#define rep(i,a) for(int i = 0;i < a;i++)
#define Rep(i,a) for(int i = 1;i <= a;i++)
#define INF 1<<30
#define MOD 1000000007

int N;
ll sA = 0, sB = 0;
vector<pair<int, int>>a;

bool cmp(pair<int, int> X, pair<int, int> Y) {
    return min(X.first, X.second) < min(Y.first, Y.second);
}

int main() {
    //ifstream inputFile("D:\\下载\\浏览器\\codeAns\\P4779_1.in");
    //streambuf* original_cin_buf = cin.rdbuf();
    //cin.rdbuf(inputFile.rdbuf());
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    cin >> N;
    a.assign(N, pair<int, int>());
    rep(i, N) {
        int ia, ib;
        cin >> a[i].first >> a[i].second;
    }
    sort(a.begin(), a.end(), cmp);
    while (a.size())
    {
        auto [ia, ib] = a.back();
        a.pop_back();
        if (sA + ia < sB + ib||(sA + ia == sB + ib && sA < sB))
            sA += ia;
        else
            sB += ib;
    }
    cout << max(sA, sB);


}