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


const int MAX = 400005;

int p[MAX];   
ll s[MAX];    
ll mx[MAX];   
int e[MAX];   
int sz[MAX];  

int find(int i) {
    return (p[i] == i) ? i : p[i] = find(p[i]);
}


void unite(int i, int j) {
    int r1 = find(i);
    int r2 = find(j);
    if (r1 != r2) {
        p[r2] = r1;
        s[r1] += s[r2];
        mx[r1] = max(mx[r1], mx[r2]);
        e[r1] += e[r2] + 1;
        sz[r1] += sz[r2];
    } else {
        e[r1]++;
    }
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);

    int n;cin >> n;

    vector<pair<int, int>> r(n);
    vector<ll> v; 
    v.reserve(2 * n);
    
    ll tot = 0; 
    for (int i = 0; i < n; ++i) {
        cin >> r[i].first >> r[i].second;
        v.push_back(r[i].first);
        v.push_back(r[i].second);
        tot += r[i].first + r[i].second;
    }

    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());

    int m = v.size();
    
    for(int i = 0; i < m; i++) {
        p[i] = i;
        s[i] = v[i];
        mx[i] = v[i];
        sz[i] = 1;
        e[i] = 0;
    }

    auto get = [&](int val) {
        return lower_bound(v.begin(), v.end(), val) - v.begin();
    };

    for (int i = 0; i < n; ++i) {
        unite(get(r[i].first), get(r[i].second));
    }

    ll rem = 0;
    
    for (int i = 0; i < m; ++i) {
        if (p[i] == i) {
            if (e[i] == sz[i]) {
                rem += s[i];
            } else {
                rem += (s[i] - mx[i]);
            }
        }
    }

    cout << tot - rem << "\n";
    return 0;
}