#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ls first
#define rs second
void solve() {
    int n, m;
    cin >> n >> m;
    priority_queue<array<int, 3>, vector<array<int, 3>>, greater<array<int, 3>>>
        pq;
    vector<vector<pair<int, int>>> e(n + 1);
    for (int i = 1; i <= m; i++) {
        int x, y, w;
        cin >> x >> y >> w;
        pq.push({w, x, y});
        e[x].push_back({y, w});
        e[y].push_back({x, w});
    }
    vector<int> p(n + 1), dis(n + 1, 0);
    iota(p.begin(), p.end(), 0);
    dis[1] = 0;
    function<int(int)> find = [&](int x) {
        return p[x] == x ? x : p[x] = find(p[x]);
    };
    vector<int> sta(n + 1);
    function<void(int, int)> change = [&](int u, int w) {
        if (dis[u] || u == 1)
            return;
        dis[u] = w;
        for (auto [v, ww] : e[u]) {
            if (sta[v])
                change(v, w);
        }
    };

    while (pq.size()) {
        auto [w, x, y] = pq.top();
        pq.pop();
        sta[x] = sta[y] = 1;
        p[find(x)] = find(y);
        if (find(x) == find(1) || find(y) == find(1)) {
            change(x, w), change(y, w);
        }
        // for (int i = 1; i <= n; i++) {
        //     cout << dis[i] << ' ';
        // }
        // cout << '\n';
    }

    auto check = [&](int x) {
        queue<int> qu;
        qu.push(n);
        vector<int> vis(n + 1);
        iota(p.begin(), p.end(), 0);
        vis[n] = 1;
        while (qu.size()) {
            auto u = qu.front();
            qu.pop();
            for (auto [v, w] : e[u]) {
                if (vis[v])
                    continue;
                if (w + dis[v] > x)
                    continue;
                vis[v] = 1;
                p[find(v)] = find(u);
                qu.push(v);
            }
        }
        return find(1) == find(n);
    };
    int l = 1, r = 2e9 + 1;
    while (l < r) {
        int mid = l + r >> 1;
        if (check(mid))
            r = mid;
        else
            l = mid + 1;
    }
    cout << l << '\n';
}
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int T = 1;
    while (T--)
        solve();
}