// #define _GLIBCXX_DEBUG #include #include #define rep(i,b) for(int i=0;i=0;i--) #define rep1(i,b) for(int i=1;i=x;i--) #define fore(i,a) for(auto i:a) #define fore1(i,a) for(auto &i:a) #define rng(x) (x).begin(), (x).end() #define rrng(x) (x).rbegin(), (x).rend() #define sz(x) ((int)(x).size()) #define pb push_back #define fi first #define se second #define pcnt __builtin_popcountll using namespace std; using namespace atcoder; using ll = long long; using ld = long double; template using mpq = priority_queue, greater>; template bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (b ll sumv(const vector&a){ll res(0);for(auto&&x:a)res+=x;return res;} bool yn(bool a) { if(a) {cout << "Yes" << endl; return 1;} else {cout << "No" << endl; return 0;}} #define dame { cout << "No" << endl; return 0;} #define dame1 { cout << -1 << endl; return 0;} #define test(x) cout << "test" << x << endl; #define deb(x,y) cout << x << " " << y << endl; #define debp(p) cout << p.fi << " " << p.se << endl; #define deb3(x,y,z) cout << x << " " << y << " " << z << endl; #define deb4(x,y,z,x2) cout << x << " " << y << " " << z << " " << x2 << endl; #define out cout << ans << endl; #define outd cout << fixed << setprecision(20) << ans << endl; #define outm cout << ans.val() << endl; #define outv fore(yans , ans) cout << yans << "\n"; #define outdv fore(yans , ans) cout << yans.val() << "\n"; #define show(x) cerr<<#x<<" = "<;using pil = pair;using pli = pair;using pii = pair;using pdd = pair; using tp = tuple; using vi = vector;using vd = vector;using vl = vector;using vs = vector;using vb = vector; using vpii = vector;using vpli = vector;using vpll = vector;using vpil = vector; using vvi = vector>;using vvl = vector>;using vvs = vector>;using vvb = vector>; using vvpii = vector>;using vvpli = vector>;using vvpll = vector;using vvpil = vector; using mint = modint998244353; using vm = vector; using vvm = vector>; vector dx={1,0,-1,0,1,1,-1,-1},dy={0,1,0,-1,1,-1,1,-1}; ll gcd(ll a, ll b) { return a?gcd(b%a,a):b;} ll lcm(ll a, ll b) { return a/gcd(a,b)*b;} #define yes {cout <<"Yes"<>n; vector> e(n); vector e2(n-1); unordered_map mp; rep(i,n-1){ int a,b,c; cin>>a>>b>>c; a--; b--; e[a].pb(edge(a,b,c)); e[b].pb(edge(b,a,c)); e2[i] = edge(a,b,c); mp[(ll)a*n + b] = i; mp[(ll)b*n + a] = i; } auto check = [&](ll mid)->bool{ bool ok = false; int root; rep(i,n-1){ if (e2[i].cost > mid){ ok = true; root = i; break; } } if (!ok) return true; int a = e2[root].from; int b = e2[root].to; vi flg(n-1); flg[root] = 2; // show(root); bool ok2; auto dfs = [&](auto dfs,int x,int pre)->void{ ll p = (ll)x*n + pre; int pi = mp[p]; flg[pi] = 1; fore(y , e[x]){ if(y.to == pre) continue; if (y.cost > mid && ok){ ok2 = false; } dfs(dfs , y.to ,x); } if (e2[pi].cost > mid || ok){ // show(x); ok = true; flg[pi] = 2; }else{ flg[pi] = 0; } return; }; ok = false; ok2 = true; dfs(dfs,a,b); ok = false; dfs(dfs,b,a); if (!ok2) return false; ll mn = LINF; ll mx = 0; rep(i,n-1){ if (flg[i] == 2){ // show(i); chmin(mn , e2[i].cost); chmax(mx , e2[i].cost); }else if(flg[i] == 1){ assert(0); } } return (mx-mn) <= mid; }; // yn(check(70)); ll l = 0,u=INF; while(u-l > 1){ ll mid = (l+u) / 2; if (check(mid)) u = mid; else l = mid; } cout << u << endl; } int main(){ solve(); return 0; }