import java.util.PriorityQueue;

import java.util.Scanner;

// Create by Inho 2018. 5. 2.

public class Study_1916 {

public static void main(String[] args){

int INF = 1000000001;

Scanner sc = new Scanner(System.in);

int N = sc.nextInt()+1;

int M = sc.nextInt();

int[] d = new int[N];

int[][] map = new int[N][N];

for(int i=0;i<N;i++){

d[i] = INF;

for(int j=0;j<N;j++){

map[i][j] = INF;

if(i==j){

map[i][j] =0;

}

}

}

for(int i=0;i<M;i++){

int first = sc.nextInt();

int second = sc.nextInt();

int value = sc.nextInt();

if(map[first][second] > value)

map[first][second]=value;

}

int start = sc.nextInt();

int end = sc.nextInt();

PriorityQueue<Integer> q = new PriorityQueue<>();

q.offer(start);

d[start] =0;

while(!q.isEmpty()){

int node = q.poll();

for(int i=1;i<N;i++){

if(d[i] > map[node][i] + d[node]){

d[i] = map[node][i] + d[node];

q.offer(i);

}

}

}

System.out.println(d[end]);

}

}