#include<iostream> 
#define MAX 10
#include<malloc.h>
#include<string.h>
#include<stdlib.h>
using namespace std;
typedef char E;
typedef struct Edge{
	E start;
	E end;
	int weight;
}*Edges;
typedef struct GraphMatrix{
	int vex,edge;
	int matrix[MAX][MAX];
	E data[MAX];
}*Graph;

Graph Create(){
	Graph g = (Graph)malloc(sizeof(GraphMatrix));
	g->vex=g->edge=0;
	memset(g->matrix,0,sizeof(g->matrix));
	return g;
}
void addVex(Graph g,E e){
	g->data[g->vex++]=e;
	
}
int getIndex(Graph g,E e){
	for(int i=0;i<g->vex;i++)
		if(g->data[i]==e)
			return i;
	return -1;
}
void addEdge(Graph g,E v1,E v2,int w,Edges e){
	int a=getIndex(g,v1);
	int b=getIndex(g,v2);
	g->matrix[a][b]=w;
	g->matrix[b][a]=w;
	
	e[g->edge].start=v1;
	e[g->edge].end=v2;
	e[g->edge].weight=w;

	g->edge++;
}

void Kruscal(Graph g){
	int vLen=g->vex;
}
int getEnds(int ends[],int i){
	while(ends[i]!=0){
		i=ends[i];
	}
	return i;
}
void Kruskal(Graph g,Edges e){
	int index=0;
	int ends[g->edge];//保存最小生成樹中每個頂點的終點 
	for(int i=0;i<g->edge;i++)
		ends[i]=0;
	//創建結果數組 ，保存最終的最小生成樹 Res 為Result的縮寫 
	Edges edgeRes =(Edges) malloc(g->edge*sizeof(struct Edge));
	
	//按照邊的權值大小排序，我已經在main里排序過了
	
	//遍歷edges數組從最小邊開始加，加一次判回路一次，沒回路就加進來（edgeRes），有回路就換下一條

	 for(int i =0;i<g->edge;i++) {
	 	//拿到第i條邊的頂點的下標start 
		int p1= getIndex(g,e[i].start);
		//拿到第i條邊的頂點的下標start 
		int p2= getIndex(g,e[i].end);
		
		//獲取p1頂點的在已有的最小生成樹中終點是？
		int m =getEnds(ends,p1);
		//獲取p2頂點的在已有的最小生成樹中終點是？
		int n =getEnds(ends,p2);
		//是否構成回路
		if(m!=n) {//不構成回路 
			ends[m] =n; //設置m 在已有最小生成樹的終點 
			edgeRes[index++]=e[i];
		}
	 }
	 //統計并打印最小生成樹
	 int temp=0;
	  for(int i =0;i<index;i++){
	  	temp+=edgeRes[i].weight;
	  }
	  cout<<temp<<endl;
	
	
}
int cmp(const void *a, const void *b){
    return ((struct Edge *)a)->weight - ((struct Edge *)b)->weight;
}

int main(){

	int n;
	cin>>n;
	Graph graph=Create();
	Edges edges;
	edges=( Edges)malloc((n*(n-1)/2)*sizeof(struct Edge));
	for(int i=0;i<n;i++){
		char e;cin>>e;
		addVex(graph,e);
	}
		
	E v1,v2;int w;
	while(cin>>v1>>v2){
		cin>>w;
		addEdge(graph,v1,v2,w,edges);
	}
	qsort(edges,graph->edge, sizeof(Edge), cmp);
	Kruskal(graph,edges);
		
}