#include <bits/stdc++.h>   using namespace std;   const long long N = 1e5 + 5;   long long n, k, dp[N], sum, pos, s1, s2, deep[N], mndp[N], ans, ss, ss1;   vector<pair<long long, long long> > g[N];   void dfs(long long x, long long p) {     dp[x] = 0;     for (long long i = 0; i < g[x].size(); ++i) {       long long y = g[x][i].first;       if (y == p) continue;       dfs(y, x);       dp[x] = max(dp[x], dp[y] + g[x][i].second);     }   }   void get_ans(long long x, long long p, long long s) {     if (max(dp[x], s) <= sum) {       sum = max(dp[x], s);       pos = x;     }     vector<long long> a(g[x].size(), 0), b(g[x].size(), 0);     for (long long i = 0; i < g[x].size(); ++i) {       long long y = g[x][i].first;       if (y != p)         a[i] = b[i] = dp[y] + g[x][i].second;       else         a[i] = b[i] = 0;       if (i > 0) a[i] = max(a[i], a[i - 1]);     }     for (long long i = (long long)b.size() - 2; i >= 0; --i) {       b[i] = max(b[i], b[i + 1]);     }     for (long long i = 0; i < g[x].size(); ++i) {       long long y = g[x][i].first;       if (y == p) continue;       long long mx = 0;       if (i > 0) mx = max(mx, a[i - 1]);       if (i + 1 < b.size()) mx = max(mx, b[i + 1]);       get_ans(y, x, max(s, mx) + g[x][i].second);     }   }   void dfs1(long long x, long long p, long long s) {     deep[x] = deep[p] + 1;     mndp[deep[x]] = min(mndp[deep[x]], max(s, dp[x]));     ans = min(ans, max(mndp[deep[x]], ss1));     vector<long long> a(g[x].size(), 0), b(g[x].size(), 0);     for (long long i = 0; i < g[x].size(); ++i) {       long long y = g[x][i].first;       if (y != p)         a[i] = b[i] = dp[y] + g[x][i].second;       else         a[i] = b[i] = 0;       if (i > 0) a[i] = max(a[i], a[i - 1]);     }     for (long long i = (long long)b.size() - 2; i >= 0; --i) {       b[i] = max(b[i], b[i + 1]);     }     for (long long i = 0; i < g[x].size(); ++i) {       long long y = g[x][i].first;       if (y == p) continue;       long long mx = 0;       if (i > 0) mx = max(mx, a[i - 1]);       if (i + 1 < b.size()) mx = max(mx, b[i + 1]);       dfs1(y, x, max(mx, s));     }   }   void dfs2(long long x, long long p, long long s) {     deep[x] = deep[p] + 1;     ans = min(ans, max(max(s, dp[x]), ss1));     if (k - deep[x] - 1 > 0) {       ans = min(ans, max(mndp[k - deep[x] - 1], max(s, dp[x])));     }     vector<long long> a(g[x].size(), 0), b(g[x].size(), 0);     for (long long i = 0; i < g[x].size(); ++i) {       long long y = g[x][i].first;       if (y != p)         a[i] = b[i] = dp[y] + g[x][i].second;       else         a[i] = b[i] = 0;       if (i > 0) a[i] = max(a[i], a[i - 1]);     }     for (long long i = (long long)b.size() - 2; i >= 0; --i) {       b[i] = max(b[i], b[i + 1]);     }     for (long long i = 0; i < g[x].size(); ++i) {       long long y = g[x][i].first;       if (y == p) continue;       long long mx = 0;       if (i > 0) mx = max(mx, a[i - 1]);       if (i + 1 < b.size()) mx = max(mx, b[i + 1]);       dfs2(y, x, max(mx, s));     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     cin >> n >> k;     for (long long i = 0; i <= n; ++i) {       mndp[i] = 1e18;     }     if (n == 1) return cout << 0, 0;     if (n == 2) {       long long x, y, z;       cin >> x >> y >> z;       if (k == 2) z = 0;       cout << z;       return 0;     }     for (long long i = 1; i < n; ++i) {       long long x, y, z;       cin >> x >> y >> z;       g[x].push_back(make_pair(y, z));       g[y].push_back(make_pair(x, z));     }     dfs(1, 0);     sum = 1e18;     pos = 0;     get_ans(1, 0, 0);     if (k == 1) return cout << sum, 0;     dfs(pos, 0);     vector<pair<long long, long long> > a(g[pos].size());     for (long long i = 0; i < g[pos].size(); ++i) {       a[i] = make_pair(dp[g[pos][i].first] + g[pos][i].second, g[pos][i].first);     }     sort(a.begin(), a.end());     reverse(a.begin(), a.end());     long long s = 0;     if (a.size() > 2)       ss = a[2].first;     else       ss = 0;     s1 = a[0].second;     s2 = a[1].second;     mndp[0] = a[0].first;     deep[pos] = 0;     ans = sum;     ss1 = a[1].first;     dfs1(s1, pos, ss);     for (int i = 1; i <= n; ++i) {       mndp[i] = min(mndp[i], mndp[i - 1]);     }     ss1 = a[0].first;     dfs2(s2, pos, ss);     cout << ans;   }