#include<iostream>
#include<queue>
#include<vector>
#include<utility>
#include<cstring>
#include<cmath>
using namespace std;
vector<pair<int, int>> a[20005];//存边
int dis[10005] = { 0 };//存放每个点的最大拥挤度
int vis[10005] = { 0 };
int main()
{
	int n = 0, m = 0, s = 0, t = 0;
	int v = 0, w = 0, u = 0;
	int num = 0x3f3f3f;
	priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>> q;
	cin >> n >> m >> s >> t;
	dis[t] = 0x3f3f3f;
	for (int i = 0; i < m; i++)
	{
		cin >> u >> v >> w;
		a[u].push_back({ w,v });
		a[v].push_back({ w,u });
	}//建图
	q.push({0,s });
	while (!q.empty())
	{
		int u1 = q.top().second;
		q.pop();
		if (vis[u1] == 1)
			continue;
		vis[u1] = 1;
		for (auto ed : a[u1])
		{
			int w1 = ed.first, v1 = ed.second;
			num = max(w1, dis[u1]);
			if (v1 != t)
			{
				dis[v1] = num;
				pair<int,int> a1 = {dis[v1],v1};
				q.push(a1);
			}
			else if (v1 == t)
			{
				dis[v1] = min(num, dis[v1]);
				//cout << dis[v1]<< endl;
			}
		}
	}
	cout << dis[t] << endl;
	return 0;
}