#include<stdio.h>
#include<string.h>

const int inf=1000000000;

int n,g[10][10];

void floyd()
{
	int i,j,k;
	for(k=0;k<n;k++)
		for(i=0;i<n;i++)
			for(j=0;j<n;j++)
				if(g[i][k]+g[k][j]<g[i][j])
					g[i][j]=g[i][k]+g[k][j];
}

int main()
{
	int m,a,b,l,i,j;
	while(scanf("%d%d",&n,&m)!=EOF)
	{
		for(i=0;i<n;i++)
			for(j=0;j<n;j++)
				g[i][j]=inf;
		while(m--)
		{
			scanf("%d%d%d",&a,&b,&l);
			g[a-1][b-1]=g[b-1][a-1]=l;
		}
		floyd();
		scanf("%d%d",&a,&b);
		if(g[a-1][b-1]==inf)
			puts("No path");
		else
			printf("%d\n",g[a-1][b-1]);
	}
	return 0;
}
/**************************************************************
	Problem: 2044
	User: admin
	Language: C++
	Result: Accepted
	Time:40 ms
	Memory:1144 kb
****************************************************************/