/*
题解后续会加详细版。。
*/
1 #include <iostream>
2 #include <cstdlib>
3 #include <cstdio>
4 #include <cstddef>
5 #include <iterator>
6 #include <algorithm>
7 #include <string>
8 #include <locale>
9 #include <cmath>
10 #include <vector>
11 #include <cstring>
12 #include <map>
13 #include <utility>
14 #include <queue>
15 #include <stack>
16 #include <set>
17 #include <functional>
18 using namespace std;
19 typedef pair<int, int> P;
20 const int INF = 0x3f3f3f3f;
21 const int modPrime = 3046721;
22 const double eps = 1e-9;
23 const int MaxN = 20010;
24 const int MaxM = 100010;
25
26 int N, M;
27 struct Node
28 {
29 int a, b, c;
30 };
31
32 Node nodeVec[MaxM];
33
34 bool Cmp(const Node n1, const Node n2)
35 {
36 return n1.c > n2.c;
37 }
38
39 /**************************************/
40 //Union-Find Sets
41
42 int ftr[MaxN << 1];
43
44 void ufsIni(int n)
45 {
46 for (int i = 0; i <= n; ++i)
47 {
48 ftr[i] = i;
49 }
50 }
51
52 int ufsFind(int x)
53 {
54 if (x == ftr[x])
55 {
56 return x;
57 }
58 return ftr[x] = ufsFind(ftr[x]);
59 }
60 /**************************************/
61
62
63 void Solve()
64 {
65 int ans = 0;
66 ufsIni((N << 1));
67 int x, y;
68 for (int i = 0; i < M; ++i)
69 {
70 x = ufsFind(nodeVec[i].a);
71 y = ufsFind(nodeVec[i].b);
72 if (x == y)
73 {
74 ans = nodeVec[i].c;
75 break;
76 }
77 ftr[x] = ufsFind(nodeVec[i].b + N);
78 ftr[y] = ufsFind(nodeVec[i].a + N);
79 }
80 printf("%d\n", ans);
81 }
82
83 int main()
84 {
85 #ifdef HOME
86 freopen("in", "r", stdin);
87 //freopen("out", "w", stdout);
88 #endif
89
90 scanf("%d %d", &N, &M);
91 for (int i = 0; i < M; ++i)
92 {
93 scanf("%d %d %d", &nodeVec[i].a, &nodeVec[i].b, &nodeVec[i].c);
94 }
95 sort(nodeVec, nodeVec + M, Cmp);
96 Solve();
97
98 #ifdef HOME
99 cerr << "Time elapsed: " << clock() / CLOCKS_PER_SEC << " ms" << endl;
100 _CrtDumpMemoryLeaks();
101 #endif
102 return 0;
103 }
