#include<iostream>
#include<cstring>
using namespace std;
int vis[101];
struct node{
	int left,right,father,value;
}t[101];
int dfs(int x,int d){
	if(!x||vis[x]) return 0;
	vis[x]=1;
	return dfs(t[x].left,d+1)+dfs(t[x].right,d+1)+dfs(t[x].father,d+1)+t[x].value*d;
}
int main(){
	int n,ans=0x7f;
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>t[i].value>>t[i].left>>t[i].right;
	}
	for(int i=1;i<=n;i++){
		t[t[i].left].father=i;
		t[t[i].right].father=i;
	}
	for(int i=1;i<=n;i++){
		memset(vis,0,sizeof(vis));
		ans=min(ans,dfs(i,0));
	}
	cout<<ans;
	return 0;
}