#include <iostream>
#include <queue>
#define MAX_N 100005
using namespace std;
long long current_ingoing[MAX_N], cost_to_switch[MAX_N], reduced[MAX_N];
pair<long long, long long> outgoing[MAX_N];
queue<long long> vertices_to_check;
bool was_checked[MAX_N];

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	long long N, t1, t2, forced_switch = 0;
	cin >> N;
	for (size_t i = 1; i <= N; i++)
	{
		cin >> t1 >> t2;
		outgoing[i] = { t1, t2 };
		current_ingoing[t1]++;
	}
	for (size_t i = 1; i <= N; i++)
	{
		if (!current_ingoing[i])
		{
			vertices_to_check.push(i);
		}
	}
	while (!vertices_to_check.empty())
	{
		long long cs = vertices_to_check.front();
		vertices_to_check.pop();
		forced_switch += cost_to_switch[cs] - reduced[cs];
		cost_to_switch[outgoing[cs].first] += outgoing[cs].second;
		reduced[outgoing[cs].first] = max(reduced[outgoing[cs].first], outgoing[cs].second);
		current_ingoing[outgoing[cs].first]--;
		if (current_ingoing[outgoing[cs].first] == 0)
		{
			vertices_to_check.push(outgoing[cs].first);
		}
		was_checked[cs] = true;
	}
	for (size_t i = 1; i <= N; i++)
	{
		if (!was_checked[i] && cost_to_switch[i])
		{
			long long curr = outgoing[i].first, cval = outgoing[i].second, lval = -1;
			was_checked[i] = true;
			do 
			{
				cval = min(cval, outgoing[curr].second);
				was_checked[curr] = true;
				curr = outgoing[curr].first;
				lval = outgoing[outgoing[curr].first].second;
			} while (curr != outgoing[i].first);
			forced_switch += min(cost_to_switch[i] + cval, cost_to_switch[i] - reduced[i] + lval);
		}
	}
	for (size_t i = 1; i <= N; i++)
	{
		long long size_track = 0;
		if (!was_checked[i])
		{
			long long curr = outgoing[i].first, cval = outgoing[i].second;
			was_checked[i] = true;
			do {
				cval = min(cval, outgoing[curr].second);
				was_checked[curr] = true;
				curr = outgoing[curr].first;
				size_track++;
			} while (curr != outgoing[i].first);
			forced_switch += cval;
		}
		if (size_track == N)
		{
			cout << 0;
			return 0;
		}
	}
	cout << forced_switch;
}