2673

#include <iostream>
#include <set>
#include <algorithm>
#include <string.h>
#include<queue>
#include<stack>
#define ll long long
using namespace std;
int n, m;
#define inf 0x3f3f3f3f
int maze[1000][1000];
void ()
{
	for (int k = 1; k <= m;k++)
	{
		for (int i = 1; i <= m;i++)
		{
			for (int j = 1; j <= m;j++)
			{
				maze[i][j] = min(maze[i][j], maze[i][k] + maze[k][j]);
			}
		}
	}
}
int main()
{
	scanf("%d%d", &m, &n);
	memset(maze,inf,sizeof maze);
	for (int i = 1; i <= n;i++)
	{
		int a, b, c;
		scanf("%d%d%d", &a, &b, &c);
		maze[a][b] = c;
		maze[b][a] = c;
	}
	int s, t;
	scanf("%d%d", &s, &t);
	floy();
	if(s==t)
	printf("0n");
	else
	printf("%dn", maze[s][t]);
}