#include<iostream>

#include<algorithm>

using namespace std;

const int maxn = 1e4 + ;

int n, m, s, t, st[maxn << ], en[maxn << ], val[maxn << ];

int l = maxn, r, ans, mid, fa[maxn];

//并查集

int getfa(int x){

    if (fa[x] == x)return x;

    return fa[x] = getfa(fa[x]);

}

//并查集判断

bool find(int x, int y){

    return getfa(x) == getfa(y);

}

//并查集合并

void H_(int x, int y){

    if (!find(x, y))fa[getfa(x)] = fa[getfa(y)];

}

bool check(int x){

    for (int i = ; i <= n; ++i)fa[i] = i;

    for (int i = ; i <= m;++i)

    if (val[i] <= x)H_(st[i], en[i]);

    return find(s, t);

}

void half(){

    while (l <= r){

        mid = (l + r) >> ;

        if (check(mid)){ ans = mid; r = mid - ; }

        else l = mid + ;

    }

}

int main(){

    cin >> n >> m >> s >> t;

    for (int i = ; i <= m; ++i)

    {

        cin >> st[i] >> en[i] >> val[i];

        l = min(l, val[i]);    r = max(r, val[i]);

    }

    half();    //二分

    cout << ans << endl;

}