#include<bits/stdc++.h>

#define int long long
#define endl '\n'
using namespace std;
const int INF = 2e9;
const int N = 3e5 + 5;
bool p[N + 5], s[N + 5];
int pre[N + 5], suf[N + 5];

struct edge {
    int u, v, w;
};
vector<edge> G;

struct DSU {
    vector<int> pre, sz;

    DSU(int n) : pre(n + 1), sz(n + 1) {
        std::iota(pre.begin(), pre.end(), 0ll);
    }

    int find(int x) {
        return pre[x] == x ? x : pre[x] = find(pre[x]);
    }

    bool same(int x, int y) {
        return find(x) == find(y);
    }

    bool merge(int x, int y) {
        int fx = find(x), fy = find(y);
        if (fx == fy) return false;
        if (sz[fx] > sz[fy]) swap(fx, fy);
        sz[fy] += sz[fx];
        pre[fx] = fy;
        return true;
    }
};

void solve() {
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++) pre[i] = suf[i] = INF, p[i] = s[i] = false;
    pre[1] = suf[n] = 0;
    p[1] = s[n] = true;
    for (int i = 1, u, v, w; i <= m; i++) {
        cin >> u >> v >> w;
        G.push_back({u, v, w});
    }
    std::sort(G.begin(), G.end(), [&](const edge a, const edge b) {
        return a.w < b.w;
    });
    int ans = INF;
    DSU dsu(n);
    for (auto [u, v, w]: G) {
        dsu.merge(u, v);
        if (!p[u] && dsu.same(1, u)) pre[u] = w, p[u] = true;
        if (!p[v] && dsu.same(1, v)) pre[v] = w, p[v] = true;
        if (!s[u] && dsu.same(n, u)) suf[u] = w, s[u] = true;
        if (!s[v] && dsu.same(n, v)) suf[v] = w, s[v] = true;
        int tmp = min(max(pre[u], suf[v]), max(pre[v], suf[u]));
        if (dsu.same(1, n)) ans = min(ans, tmp + w);
    }
    cout << ans << '\n';
}

signed main() {
    int t = 1;
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    while (t--) solve();
}