#include<iostream>
#include<cstdio>
#include<cstdlib>
#define  leiyujie best
using namespace std;
const int maxn=99999999;
int a[101];
int g[101][101];
int main()
{
	int n,l,r,min,total;
	freopen("hospital.in","r",stdin);
	freopen("hospital.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
		g[i][j]=maxn;
		for(int i=1;i<=n;i++)
		{
			g[i][i]=0;
			cin>>a[i]>>l>>r;
			if(l>0)g[i][l]=g[l][i]=1;
			if(r>0)	g[i][r]=g[r][i]=1;
			
		}
		for(int k=1;k<=n;k++)
			for(int i=1;i<=n;i++)
			if(i!=k)
				for(int j=1;j<=n;j++)
				if(i!=j&&k!=j&&g[i][k]+g[k][j]<g[i][j])
					g[i][j]=g[i][k]+g[k][j];
		min=0x7fffffff;
		for(int i=1;i<=n;i++)
		{
			total=0;
			for(int j=1;j<=n;j++)
			total+=g[i][j]*a[j];
			if(total<min)min=total;
		}
		cout<<min<<endl;
		return 0;
}