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

#define all(x) begin(x), end(x)
#ifdef CKISEKI
#include <experimental/iterator>
#define debug(a...) debug_(#a, a)
#define orange(a...) orange_(#a, a)
void debug_(auto s, auto ...a) {
  cerr << "\e[1;32m(" << s << ") = (";
  int f = 0;
  (..., (cerr << (f++ ? ", " : "") << a));
  cerr << ")\e[0m\n";
}
void orange_(auto s, auto L, auto R) {
  cerr << "\e[1;33m[ " << s << " ] = [ ";
  using namespace experimental;
  copy(L, R, make_ostream_joiner(cerr, ", "));
  cerr << " ]\e[0m\n";
}
#else
#define safe ((void)0)
#define debug(...) safe
#define orange(...) safe
#endif

struct Dsu {
  vector<int> pa, rk;
  Dsu(int n) : pa(n), rk(n) {
    iota(all(pa), 0);
  }
  int anc(int x) {
    return x==pa[x] ? x : pa[x]=anc(pa[x]);
  }
  bool join(int x, int y) {
    x = anc(x);
    y = anc(y);
    if (x == y) return false;
    if (rk[x] < rk[y]) swap(x, y);
    if (rk[x] == rk[y]) ++rk[x];
    pa[y] = x;
    return true;
  }
};

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n, m;
  cin >> n >> m;

  int ans = 2e9;
  vector<tuple<int,int,int>> e;
  for (int i = 0; i < m; i++) {
    int u, v, w;
    cin >> u >> v >> w;
    --u, --v;
    e.emplace_back(w, u, v);
    tie(u, v) = minmax(u, v);
    if (u == 0 && v == n - 1)
      ans = min(ans, w);
  }
  ranges::sort(e);

  Dsu dsu(n);
  vector<vector<pair<int,int>>> g(n);
  for (auto [w, u, v] : e) {
    if (dsu.join(u, v)) {
      g[u].emplace_back(w, v);
      g[v].emplace_back(w, u);
    }
  }

  const auto dfs = [&](auto self, vector<int> &d, int i, int f) -> void {
    for (auto [w, j] : g[i]) {
      if (j == f) continue;
      d[j] = max(d[i], w);
      self(self, d, j, i);
    }
  };

  vector<int> d1(n), dn(n);
  dfs(dfs, d1, 0, -1);
  dfs(dfs, dn, n - 1, -1);

  orange(all(d1));
  orange(all(dn));

  for (int i = 0; i < n; i++) {
    if (i == 0 || i == n - 1) continue;
    ans = min(ans, d1[i] + dn[i]);
  }

  cout << ans << '\n';

  return 0;
}