#include <bits/stdc++.h>

#define x first
#define y second
#define el '\n'
#define debug(x) cout << #x << ": " << x << endl
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int N = 3e5 + 10, INF = 0x3f3f3f3f, mod = 998244353;

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int n, m; cin >> n >> m;
    vector<vector<pii>> G(n + 1);
    priority_queue<tuple<int, int, int>, vector<tuple<int, int, int>>, greater<tuple<int, int, int>>> e;
    int ans = 2e9;
    for (int i = 0; i < m; ++i) {
        int u, v, w; cin >> u >> v >> w;
        G[u].emplace_back(v, w), G[v].emplace_back(u, w);
        e.push({w, u, v});
    }
    vector<int> fa(n + 1);
    iota(fa.begin(), fa.end(), 0);
    function<int(int)> find = [&](int x) {
        return fa[x] == x ? x : fa[x] = find(fa[x]);
    };
    vector<bool> st(n + 1);
    priority_queue<pii, vector<pii>, greater<pii>> Q;
    Q.push({0, 1});
    while (Q.size()) {
        auto[d, u] = Q.top(); Q.pop();
        while (e.size() && get<0>(e.top()) < d) {
            auto[w, a, b] = e.top(); e.pop();
            fa[find(a)] = find(b);
        }
        if (st[u]) continue;
        st[u] = 1;
        for (auto[v, k]: G[u]) {
            if (find(v) == find(n) && k >= d) ans = min(ans, k + d);
            if (!st[v]) Q.push({max(k, d), v});
        }
    }
    cout << ans << el;
}