#include <bits/stdc++.h>
using namespace std;

class DSU {
    public:
        vector<int> id;
        DSU(int n){
            id.resize(n);
            for (int i = 0; i < n; ++i) id[i] = i;
        }
        int find(int u) {
            if (id[u] == u) return u;
            return id[u] = find(id[u]);
        }

        void unionThese(int u, int v) {
            int idU = find(u), idV = find(v);
            id[idU] = idV;
        }
};

int main(){
    int n, m; cin >> n >> m;
    vector<vector<pair<int, int>>> adj(n + 1);
    vector<vector<int>> edges(m);
    for (int i = 0; i < m; ++i) {
        int u, v, w; cin >> u >> v >> w;
        adj[u].push_back({v,w});
        adj[v].push_back({u,w});
        edges[i] = {w, u, v};
    }
    sort(edges.begin(), edges.end());
    DSU uf = *(new DSU(n + 1));
    vector<vector<pair<int, int>>> res(n + 1);
    for (int i = 0; i < edges.size(); ++i) {
        vector<int> edge = edges[i];
        int u = edge[1], v = edge[2], w = edge[0];
        if (uf.find(u) != uf.find(v)) {
            cout << u << " " << v << endl;
            res[u].push_back({v, w});
            res[v].push_back({u, w});
            uf.unionThese(u, v);
        }
    }
    vector<int> vis(n + 1); vector<pair<int, int>> ans(n + 1);
    for (int i = 0; i < n + 1; ++i) ans[i] = {-1, -1};
    queue<int> q; q.push(1); vis[1] = 1;
    while (!q.empty()) {
        int front = q.front(); q.pop();
        for (auto i : res[front]) {
            if (i.second >= ans[front].first) {
                ans[i.first].second = ans[front].first;
                ans[i.first].first = i.second;
            } else if (i.second > ans[front].second) {
                ans[i.first].second = i.second;
            }
            if (!vis[i.first]) {
                q.push(i.first);
                vis[i.first] = 1;
            }
        }
    }
    cout << ans[n].first + max(0, ans[n].second);
    return 0;
}