#include<iostream>
#include<cmath>
using namespace std;
struct node
{
	int father, left, right, value;
}h[105];

int ans = INT16_MAX, sum, vis[105];

void dfs(int pos, int step)
{
	sum += step * h[pos].value;
	int fa = h[pos].father, l = h[pos].left, r = h[pos].right;

	if (fa && vis[fa] != 1)
	{
		vis[fa] = 1;
		dfs(fa, step+1);
	}
	if (l && vis[l] != 1)
	{
		vis[l] = 1;
		dfs(l, step+1);
	}
	if (r && vis[r] != 1)
	{
		vis[r] = 1;
		dfs(r, step+1);
	}
}

int main()
{
	int cnt;
	cin >> cnt;
	for (int i = 1; i <= cnt; i++)
	{
		cin >> h[i].value >> h[i].left >> h[i].right;
		h[h[i].left].father = i;
		h[h[i].right].father = i;
	}

	for (int j = 1; j <= cnt; j++)
	{
		sum = 0;
		memset(vis, 0, sizeof(vis));
		vis[j] = 1;
		dfs(j, 0);
		ans = min(ans, sum);
	}

	cout << ans;
}