#include<cstdio>
	#include<cstring>
	#include<cmath>
	#include<algorithm>
	#include<iostream>
	#include<queue>
	using namespace std;
	int N,M,s,t,p=0;
	int head[10000010],dis[10000010],vis[10000010];
	struct edge
	{
		int to,v,nex;
	}e[10000010];
	void add(int a,int b,int c)
	{
		e[++p].v=c;
		e[p].to=b;
		e[p].nex=head[a];
		head[a]=p;
	}
	struct node
	{
		int dis,pos;
		bool operator < (const node &a) const
		{
			return dis<a.dis;
		}
	};
	priority_queue <node> q;
	void Dij()
	{
		memset(dis,0x3f,sizeof(dis));
		memset(vis,0,sizeof(vis));
		dis[s]=0;
		q.push((node){0,s});
		while(!q.empty())
		{
			node tmp=q.top();
			q.pop();
			int x=tmp.pos;
			if(vis[x]) continue;
			vis[x]=1;
			int c=head[x];
			while(c)
			{
				int pd=e[c].to;
				if(dis[pd]>max(dis[x],e[c].v))
				{
					dis[pd]=max(dis[x],e[c].v);
					if(!vis[pd]) q.push((node){dis[pd],pd});
				}
				c=e[c].nex;
			}
		}
	
	}
	int main()
	{
		scanf("%d %d %d %d",&N,&M,&s,&t);
		int u,v,e;
		for(int i=1;i<=M;i++)
		{
			scanf("%d %d %d",&u,&v,&e);
			add(u,v,e);
			add(v,u,e);
		}
		Dij();
		printf("%d",dis[t]);
		return 0;
	}