// // Created by Administrator on 2023/8/8. //

include "set"

include

include <limits.h>

include

using namespace std; const int MAX_VERTICES = 100; // 最大顶点数量 struct Graph {

int numVertices; // 图的顶点数量
int adjacencyMatrix[MAX_VERTICES][MAX_VERTICES]; // 邻接矩阵
// 构造函数
Graph(int n) {
    numVertices = n;
    // 初始化邻接矩阵为无穷大
    for (int i = 1; i <= numVertices; i++) {
        for (int j = 1; j <= numVertices; j++) {
            adjacencyMatrix[i][j] = INT_MAX;
        }
    }
}

};

struct Graph1 {

int numVertices; // 图的顶点数量
int adjacencyMatrix[MAX_VERTICES][MAX_VERTICES]; // 邻接矩阵
// 构造函数
Graph1(int n) {
    numVertices = n;
    // 初始化邻接矩阵为无穷大
    for (int i = 1; i <= numVertices; i++) {
        for (int j = 1; j <= numVertices; j++) {
            adjacencyMatrix[i][j] = 0;
        }
    }
}

};

typedef struct EdgeS{

int F;
int T;
int W;

}; bool cmp(struct EdgeS a , struct EdgeS b){

return a.W<b.W;

} bool visited[MAX_VERTICES] = {false}; bool cmp1(struct EdgeS a , struct EdgeS b){

return a.W>b.W;

} // 添加边 void addEdge(Graph &G , int numOfEdge, EdgeS *E1) {

int a , b ,w;
for (int i = 1; i <= numOfEdge ; ++i) {
    cin>>a>>b>>w;
    G.adjacencyMatrix[a][b] = 1;
    G.adjacencyMatrix[b][a] = 1; // 如果是有向图则省略这行

    E1[i].F = a;
    E1[i].T = b;
    E1[i].W = w;
}

}

bool dfs(Graph1 G,int s,int t,int m,bool visited[MAX_VERTICES]){

visited[s] = true;
for (int i = 1; i <= m; ++i) {
    if (G.adjacencyMatrix[s][i] == 1 && !visited[i]) {
        if (i == t){
            return true;
        }
        if(dfs(G,i,t,m, visited)){
            return true;
        }
    }
}
return false;

}

void kruskal(Graph &G,Graph1 &G1,EdgeS *E1,int m, int s,int t){

EdgeS E2[m-1];
set<int> set1;
set<int> set2;
int j = 0;

for (int i = 1; i <= m; ++i) {
    int x = E1[i].F;
    int y = E1[i].T;

    if (set1.find(E1[i].F)==set1.end()||set1.find(E1[i].T)==set1.end()){
        E2[j].F = E1[i].F;
        E2[j].T = E1[i].T;
        E2[j++].W = E1[i].W;
        G1.adjacencyMatrix[x][y] = 1;
        G1.adjacencyMatrix[y][x] = 1;
    }
    int t1 = 0;
    if (set2.size()==2){
        t1 = 1;
    }
    if (x == s||x == t||t1){
        if (!t1){
            set2.insert(y);
        }
        if (set2.size()==2){
            if (dfs(G1,s,t,m,visited)){
                sort(E2,E2+j, cmp1);
                cout<<E2[0].W;
                return;
            }
        }
        for (int k = 1; k <= m; ++k) {
            visited[k] = false;
        }
    }

    if (y == t||y == s||t1){
        if (!t1){
            set2.insert(y);
        }
        if (set2.size()==2){
            if (dfs(G1,s,t,m,visited)){
                sort(E2,E2+j, cmp1);
                cout<<E2[0].W;
                return;
            }
        }
        for (int k = 1; k <= m; ++k) {
            visited[k] = false;
        }
    }

}

}

int main() { // cout<<"请输入图的顶点数和边数：";

int n , m,s,t;
cin>>n>>m>>s>>t;
EdgeS E1[m];
Graph g(n);
Graph1 g1(n);
// 添加边
addEdge(g, m, E1);
sort(E1+1,E1+m+1, cmp);
kruskal(g,g1,E1,m,s,t);
return 0;

}