#include <vector>
#include <cmath>
#include <cstdio>
#include <queue>
#include <cstring>
#include <iostream>
using namespace std;
 
#define N 100010
#define LL long long
#define inf 0x7f7f7f7f
#define mem(a,n) memset(a,n,sizeof(a))
 
int read()
{
    int num=0,flag=1;char c;
    while((c=getchar())<'0'||c>'9') if(c=='-') flag=-1;
    while(c>='0'&&c<='9') { num=num*10+c-48; c=getchar();}
    return num*flag;
}
 
struct node{  
    int v,w;  
    node(){}  
    node(int V,int W){v=V;w=W;}  
    bool operator < (const node &rhs) const {
		return rhs.w>w;
	}
};
 
int dis[N],n,m,a[N],s,vis[N],t;
vector<node> G[N];
 
void dijkstra() {
	for(int i=1;i<=n;i++)
		dis[i]=inf;
    dis[s]=0;
	priority_queue<node> q;
	q.push( node(s,0) );
	while(!q.empty()) {
		node x=q.top();q.pop();
		for(int i=0;i<G[x.v].size();i++) {
			node y=G[x.v][i];
			if(dis[y.v]>x.w+y.w) {
				dis[y.v]=x.w+y.w;
				q.push( node(y.v,dis[y.v]) );
			}
		}
	}
}
 
int main()
{
   	n=read();m=read();
    for(int i=1,u,v,w;i<=m;i++) {
    	u=read(),v=read(),w=read();
    	G[u].push_back( node(v,w) );
    	G[v].push_back( node(u,w) );
	}
	s=read();t=read();
	dijkstra();
    cout<<dis[t];
}