#include <bits/stdc++.h>
using namespace std;
const int MAXN = 10000;
const int MAXM = 20000;
struct Edge
{
    int u, v, w;
};
Edge e[MAXM + 5];
int n, m, s, t;
bool cmp(Edge a, Edge b)
{
    return a.w < b.w;
}
int fa[MAXN + 5];
int cnt[MAXN + 5];
int findFa(int x)
{
    if (fa[x] == x)
        return x;
    return fa[x] = findFa(fa[x]);
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m >> s >> t;
    if (s == t)
    {
        cout << 0;
        return 0;
    }
    for (int i = 1; i <= m; i++)
        cin >> e[i].u >> e[i].v >> e[i].w;
    // 并查集初始化
    for (int i = 1; i <= n; i++)
    {
        fa[i] = i;
        cnt[i] = 1;
    }
    // kruskal 算法
    sort(e + 1, e + m + 1, cmp);
    int sum = 0;
    for (int i = 1; i <= m; i++)
    {
        int u = e[i].u;
        int v = e[i].v;
        int w = e[i].w;
        int faU = findFa(u);
        int faV = findFa(v);
        if (faU != faV)
        {
            if (cnt[faU] < cnt[faV])
            {
                fa[faU] = faV;
                cnt[faV] += cnt[faU];
            }
            else
            {
                fa[faV] = faU;
                cnt[faU] += cnt[faV];
            }
            if (findFa(s) == findFa(t))
            {
                cout << w << "\n";
                return 0;
            }
        }
    }
    return 0;
}