#include "bits/stdc++.h"
#pragma GCC optimize(3)

#define ll long long
const int inf = 2100000000;

using namespace std;
#define IOS ios::sync_with_stdio(0),cin.tie(0);
#define irep(i, l, r) for(int i = (l); i <= (r); ++ i)
array<int, 3> e[1000009];
const int N = 300099;
int fa[N], sz[N];
inline int find(int x){
    if(fa[x] == x)return x;
    fa[x] = find(fa[x]);
    return fa[x];
}

void solve() {
    int n, m;
    cin >> n >> m;
    vector<int>a(n, inf), b(n, inf);
  //  vector<int>fa(n);
    irep(i, 0, m - 1){
        int u, w, v;
        cin  >> u >>v >>w;
        e[i] = {w, u - 1, v - 1};
    }
    irep(i, 0, n - 1)
        fa[i] = i;
    sort(e, e + m);

    int ans = inf;
    a[0] = 0, b[n - 1] = 0;

    vector<vector<int>>it(n);

    auto merge = [&](int x,int y, int tag)->void{
        x = find(x), y = find(y);
        if(x == y)return;
        if(x == find(0)){
            for(int i : it[y]){
                a[i] = tag;
            }
        }

        if(y == find(0)){
            for(int i :it[x]){
                a[i] = tag;
            }
        }
        if(x == find(n - 1)){
            for(int i : it[y]){
                b[i] = tag;
            }
        }
        if(y == find(n - 1)){
            for(int i :it[x]){
                b[i] = tag;
            }
        }

        if(sz[x] < sz[y]){
            for(int ii : it[x]){
                it[y].emplace_back(ii);
            }
            it[x].clear();
            it[x].shrink_to_fit();
            sz[y] += sz[x];
            fa[x] = y;
        }
        else{
            for(int ii : it[y]){
                it[x].emplace_back(ii);
            }
            it[y].clear();
            it[y].shrink_to_fit();
            sz[x] += sz[y];
            fa[y] = x;
        }

    };
    irep(i, 0, n - 1){
        sz[i] = i, it[i].emplace_back(i);
    }

    for(int i = 0; i < m; ++ i){
        auto [w, u, v] = e[i];
        merge(u, v, w);
    }

    for(int i = 0; i < m; ++ i){
        auto [w, u, v] = e[i];
        if (min(max(a[u], b[v]), max(a[v], b[u])) > w)continue;
        ans = min({ans, max(a[u], b[v]) + w, max(a[v], b[u]) + w});
    }
    cout << ans;
}

int main(){
    IOS
    int t = 1;
    while (t--)solve();
}
/*
 * 3 2
1 2 1000000000
2 3 1000000000
 */