#include <iostream>
#include <vector>
#include <queue>
#include <limits>
 
const int INF = std::numeric_limits<int>::max();
 
struct Edge {
    int destination;
    int weight;
};
 
// Hàm tìm tải trọng lớn nhất trên đường đi từ thành phố s đến thành phố t
int findMaxLoad(const std::vector<std::vector<Edge>>& graph, int n, int s, int t) {
    std::vector<int> maxLoad(n + 1, 0);
    std::priority_queue<std::pair<int, int>> pq;
 
    maxLoad[s] = INF;
    pq.push({INF, s});
 
    while (!pq.empty()) {
        int load = pq.top().first;
        int currentCity = pq.top().second;
        pq.pop();
 
        if (currentCity == t) {
            return load;
        }
 
        if (load <= maxLoad[currentCity]) {
            for (const Edge& edge : graph[currentCity]) {
                int newLoad = std::min(load, edge.weight);
                if (newLoad > maxLoad[edge.destination]) {
                    maxLoad[edge.destination] = newLoad;
                    pq.push({newLoad, edge.destination});
                }
            }
        }
    }
 
    return 0;
}
 
int main() {
    int n, m, s, t;
    std::cin >> n >> m >> s >> t;
 
    std::vector<std::vector<Edge>> graph(n + 1);
 
    for (int i = 0; i < m; i++) {
        int x, y, z;
        std::cin >> x >> y >> z;
        graph[x].push_back({y, z});
        graph[y].push_back({x, z});
    }
 
    int maxLoad = findMaxLoad(graph, n, s, t);
 
    std::cout << maxLoad << std::endl;
 
    return 0;
}

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