#include<iostream>
#define Mmax 500005
#define Nmax 250005
using namespace std;
typedef struct Muchie {int e1,e2,cost;};
Muchie G[Mmax];
int n,m,x,y,h[Nmax],tata[Nmax];

void read()
{
    freopen("pscnv.in","r",stdin);
    scanf("%d %d %d %d",&n,&m,&x,&y);
    for(int i=1;i<=m;++i) {
        scanf("%d %d %d", &G[i].e1, &G[i].e2, &G[i].cost);
    }
}

void CombHeap(int i,int k)
{
    int tata=i,fiu=i*2;
    Muchie v=G[i];
    while(fiu<=k)
    {
        if(fiu<k)
            if(G[fiu].cost<G[fiu+1].cost) fiu++;
        if(v.cost<G[fiu].cost)
        {
            G[tata]=G[fiu];
            tata=fiu;
            fiu=fiu*2;
        }
        else fiu=k+1;
    }
    G[tata]=v;
}

void create_heap()
{
    for(int i=m/2;i;i--)
        CombHeap(i,m);
}

void heapsort()
{
    Muchie aux;
    create_heap();
    for(int i=m;i>1;i--)
    {
        aux=G[1];
        G[1]=G[i];
        G[i]=aux;
        CombHeap(1,i-1);
    }
}

void Union_ponderare(int x,int y)
{
    if(h[x]>h[y]) tata[y]=x;
    else
    {
        tata[x]=y;
        if(h[x]==h[y]) h[y]++;
    }
}


int Find_compresie(int x)
{
    int r=x,y=x,help;
    while(tata[r]) r=tata[r];
    while(y!=r)
    {
        help=tata[y];
        tata[y]=r;
        y=help;
    }
    return r;
}


int main()
{
    read();
    heapsort();
    int i=1,ans=0,j=0;
    while(Find_compresie(x)!=Find_compresie(y))
    {
        if(Find_compresie(G[i].e1)!=Find_compresie(G[i].e2))
        {
            ans=G[i].cost;
            ++j;
            Union_ponderare(Find_compresie(G[i].e1),Find_compresie(G[i].e2));
        }
        i++;
    }
    freopen("pscnv.out","w",stdout);
    cout<<ans;
}