1. #include <iostream>
2. #include <vector>
3. #include <algorithm>
4.  
5. struct Edge {
6.     Edge(int dest, int we) {
7.         this->dest = dest;
8.         this->weight = we;
9.     }
10.     int dest, weight;
11. };
12.  
13. const int MAXN = 54321;
14. bool used[MAXN];
15. int count = 0, tin[MAXN], fup[MAXN];
16.  
17. void DfsBriges(int vertex, int parent, std::vector<std::vector<Edge>> &graph, int &answ) {
18.     used[vertex] = true;
19.     tin[vertex] = count;
20.     fup[vertex] = count++;
21.     for (Edge edge:graph[vertex]) {
22.         int dest = edge.dest;
23.         if (dest == parent) {
24.             continue;
25.         }
26.         if (used[dest]) {
27.             fup[vertex] = std::min(fup[vertex], fup[dest]);
28.         } else {
29.             DfsBriges(dest, vertex, graph, answ);
30.             fup[vertex] = std::min(fup[vertex], fup[dest]);
31.             if (fup[dest] > tin[vertex]) {
32.                 answ = std::min(answ, edge.weight);
33.             }
34.         }
35.     }
36. }
37.  
38. int main() {
39.     int nn, mm;
40.     std::cin >> nn >> mm;
41.     std::vector<std::vector<Edge>> graph(nn + 1);
42.     for (int i = 0; i < mm; ++i) {
43.         int source, dest, weight;
44.         std::cin >> source >> dest >> weight;
45.         graph[source].push_back(Edge(dest, weight));
46.         graph[dest].push_back(Edge(source, weight));
47.     }
48.     int answ = 1e9;
49.     DfsBriges(1, -1, graph, answ);
50.     if (answ < 1e9) {
51.         std::cout << answ;
52.     } else {
53.         std::cout << -1;
54.     }
55. }
56.