#include #pragma GCC optimize("unroll-loops") using namespace std; using std::cout; using std::cin; using std::endl; using ll=long long; using ld=long double; const ll ILL=2167167167167167167; const int INF=2100000000; const int mod=998244353; #define rep(i,a,b) for (int i=(int)(a);i<(int)(b);i++) #define all(p) p.begin(),p.end() template using _pq = priority_queue, greater>; template ll LB(vector &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();} template ll UB(vector &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();} template bool chmin(T &a,T b){if(a>b){a=b;return 1;}else return 0;} template bool chmax(T &a,T b){if(a void So(vector &v) {sort(v.begin(),v.end());} template void Sore(vector &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});} void yneos(bool a,bool upp=0){if(a) cout<<(upp?"YES\n":"Yes\n"); else cout<<(upp?"NO\n":"No\n");} template void vec_out(vector &p,int ty=0){ if(ty==2){cout<<'{';for(int i=0;i<(int)p.size();i++){if(i){cout<<",";}cout<<'"'< T vec_min(vector &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;} template T vec_max(vector &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;} template T vec_sum(vector &a){T ans=T(0);for(auto &x:a) ans+=x;return ans;} int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;} //https://trap.jp/post/1702/ template struct RerootingDP { struct edge{ int from, to, idx, rev_idx; }; RerootingDP (int _n = 0) : n(_n) { es.resize(n);} void add_edge(int u, int v, int idx1, int idx2){ es[u].push_back({u,v,idx1,idx2}); es[v].push_back({v,u,idx2,idx1}); } V build(int v = 0){ root = v; vis.resize(n,0); outs.resize(n); return dfs(root); } vector reroot(){ reverse_edge.resize(n); reverse_edge[root] = e(); answers.resize(n); bfs(root); return answers; } private: int n, root; vector> es; vector vis; vector> outs; vector reverse_edge; vector answers; V dfs(int v){ vis[v]++; E val = e(); for (auto &p : es[v]){ if (vis[p.to] > 0 && p.to != es[v].back().to) swap(p,es[v].back()); if (vis[p.to] > 0) continue; E nval = put_edge(dfs(p.to),p.idx); outs[v].emplace_back(nval); val = merge(val,nval); } return put_vertex(val,v); } void bfs(int v){ int siz = outs[v].size(); vector lui(siz+1), rui(siz+1); lui[0] = e(), rui[siz] = e(); for (int i = 0; i < siz; i++) lui[i+1] = merge(lui[i],outs[v][i]); for (int i = siz-1; i >= 0; i--) rui[i] = merge(outs[v][i],rui[i+1]); for (int i = 0; i < siz; i++){ reverse_edge[es[v][i].to] = put_edge(put_vertex(merge(merge(lui[i],rui[i+1]),reverse_edge[v]),v),es[v][i].rev_idx); bfs(es[v][i].to); } answers[v] = put_vertex(merge(lui[siz],reverse_edge[v]), v); } }; struct reroot_F{ int black; int white; int large; }; reroot_F merge(reroot_F a, reroot_F b){ return {a.black+b.black,a.white+b.white,a.large+b.large}; } reroot_F e(){ return {0,0,0}; } reroot_F put_edge(reroot_F v, int i){ return v; } reroot_F put_vertex(reroot_F e, int v){ e.black=e.white+1; e.white=e.large; e.large=max(e.black,e.white); return e; } #define reroot_calc reroot_F,reroot_F,merge,e,put_edge,put_vertex void solve(); // oddloop int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int t=1; //cin>>t; rep(i,0,t) solve(); } void solve(){ int N; cin>>N; RerootingDP G(N); rep(i,0,N-1){ int a,b; cin>>a>>b; G.add_edge(a-1,b-1,0,0); } G.build(); auto res=G.reroot(); int ans=INF; rep(i,0,N) chmin(ans,res[i].black); cout<