#include<bits/stdc++.h>
using namespace std;
const int N=110;
vector<int> g[N];
int w[N]; 
int dfs(int u,int father,int d)
{
	int sum=d*w[u]; //当前点
	for(auto j:g[u])
	{
		if(j==father) continue;
		sum+=dfs(j,u,d+1); //累加子树
	}
	return sum;
}
int main()
{
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		int l,r;
		cin>>w[i]>>l>>r;
		if(l) g[i].push_back(l),g[l].push_back(i);
		if(r) g[i].push_back(r),g[r].push_back(i); 
	}
	int res=2e9;
	for(int i=1;i<=n;i++)
	{
		//cout<<dfs(i,1,0); 
		res=min(res,dfs(i,-1,0));
	}
	cout<<res;
	return 0;
}