#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n; cin >> n;
	vector<pair<int, P>>edge;
	long long ans = 0;
	rep(i, n) {
		int c, d; cin >> c >> d;
		if (0 != i)edge.push_back({ d,{i,i - 1} });
		edge.push_back({ c,{n,i} });
		ans += c;
	}
	sort(all(edge));
	dsu uf(n + 1);
	rep(i, edge.size()) {
		auto c = edge[i].first;
		int x = edge[i].second.first;
		int y = edge[i].second.second;
		if (uf.same(x, y))continue;
		ans += c;
		uf.merge(x, y);
	}
	cout << ans << endl;
	return 0;
}