#include #define overload4(_1, _2, _3, _4, name, ...) name #define rep1(i, n) for (ll i = 0; i < ll(n); ++i) #define rep2(i, s, n) for (ll i = ll(s); i < ll(n); ++i) #define rep3(i, s, n, d) for(ll i = ll(s); i < ll(n); i+=d) #define rep(...) overload4(__VA_ARGS__,rep3,rep2,rep1)(__VA_ARGS__) #define rrep1(i, n) for (ll i = ll(n)-1; i >= 0; i--) #define rrep2(i, n, t) for (ll i = ll(n)-1; i >= (ll)t; i--) #define rrep3(i, n, t, d) for (ll i = ll(n)-1; i >= (ll)t; i-=d) #define rrep(...) overload4(__VA_ARGS__,rrep3,rrep2,rrep1)(__VA_ARGS__) #define all(a) a.begin(),a.end() #define rall(a) a.rbegin(),a.rend() #define SUM(a) accumulate(all(a),0LL) #define MIN(a) *min_element(all(a)) #define MAX(a) *max_element(all(a)) #define popcount(x) __builtin_popcountll(x) #define pb push_back #define eb emplace_back #ifdef __LOCAL #define debug(...) { cout << #__VA_ARGS__; cout << ": "; print(__VA_ARGS__); cout << flush; } #else #define debug(...) void(0) #endif #define INT(...) int __VA_ARGS__;scan(__VA_ARGS__) #define LL(...) ll __VA_ARGS__;scan(__VA_ARGS__) #define STR(...) string __VA_ARGS__;scan(__VA_ARGS__) #define CHR(...) char __VA_ARGS__;scan(__VA_ARGS__) #define DBL(...) double __VA_ARGS__;scan(__VA_ARGS__) #define LD(...) ld __VA_ARGS__;scan(__VA_ARGS__) using namespace std; using ll = long long; using ld = long double; using P = pair; using LP = pair; using vi = vector; using vvi = vector; using vl = vector; using vvl = vector; using vd = vector; using vvd = vector; using vs = vector; using vc = vector; using vvc = vector; using vb = vector; using vvb = vector; using vp = vector

; using vvp = vector; template istream &operator>>(istream &is, pair &p) { return is >> p.first >> p.second; } template ostream &operator<<(ostream &os, const pair &p) { return os << '{' << p.first << ", " << p.second << '}'; } template istream &operator>>(istream &is, tuple &t) { return is >> get<0>(t) >> get<1>(t) >> get<2>(t); } template ostream &operator<<(ostream &os, const tuple &t) { return os << '{' << get<0>(t) << ", " << get<1>(t) << ", " << get<2>(t) << '}'; } template istream &operator>>(istream &is, vector &v) { for (T &t:v) { is >> t; } return is; } template ostream &operator<<(ostream &os, const vector &v) { os << '['; rep(i, v.size())os << v[i] << (i == int(v.size() - 1) ? "" : ", "); return os << ']'; } template void vecout(const vector &v, char div = '\n') { rep(i, v.size()) cout << v[i] << (i == int(v.size() - 1) ? '\n' : div); } template bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; } template bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; } void scan() {} template void scan(Head &head, Tail &... tail) { cin >> head; scan(tail...); } template void print(const T &t) { cout << t << '\n'; } template void print(const Head &head, const Tail &... tail) { cout << head << ' '; print(tail...); } template void fin(const T &... a) { print(a...); exit(0); } struct Init_io { Init_io() { ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); cout << boolalpha << fixed << setprecision(15); cerr << boolalpha << fixed << setprecision(15); } } init_io; const string yes[] = {"no", "yes"}; const string Yes[] = {"No", "Yes"}; const string YES[] = {"NO", "YES"}; const int inf = 1001001001; const ll linf = 1001001001001001001; template vector cumsum(const vector &v, bool shift_one = true) { int n = v.size(); vector res; if (shift_one) { res.resize(n + 1); rep(i, n) res[i + 1] = res[i] + v[i]; } else { res.resize(n); if (n) { res[0] = v[0]; rep(i, 1, n) res[i] = res[i - 1] + v[i]; } } return res; } vvi graph(int n, int m, bool directed = false, int origin = 1) { vvi G(n); rep(_, m) { INT(u, v); u -= origin, v -= origin; G[u].pb(v); if (!directed) G[v].pb(u); } return G; } template vector>> weighted_graph(int n, int m, bool directed = false, int origin = 1) { vector>> G(n); rep(_, m) { int u, v; T w; scan(u, v, w); u -= origin, v -= origin; G[u].eb(v, w); if (!directed) G[v].eb(u, w); } return G; } template class dinic { struct edge { int to, rev; T cap; edge(int to, T cap, int rev) : to(to), cap(cap), rev(rev) {} }; int n; vector> G; vi level, iter; void bfs(int s) { level.assign(n, -1); queue q; level[s] = 0; q.push(s); while (!q.empty()) { int v = q.front(); q.pop(); for (auto &e : G[v]) { if (e.cap > 0 && level[e.to] < 0) { level[e.to] = level[v] + 1; q.push(e.to); } } } } T dfs(int v, int t, T f) { if (v == t) return f; for (int &i = iter[v]; i < G[v].size(); i++) { auto &e = G[v][i]; if (e.cap > 0 && level[v] < level[e.to]) { T d = dfs(e.to, t, min(f, e.cap)); if (d > 0) { e.cap -= d; G[e.to][e.rev].cap += d; return d; } } } return 0; } public: explicit dinic(int n) : n(n), G(n), level(n), iter(n) {} void add_edge(int from, int to, T cap) { G[from].eb(to, cap, G[to].size()); G[to].eb(from, 0, G[from].size() - 1); } // O(|E||V|^2) T max_flow(int s, int t) { T fl = 0; while (true) { bfs(s); if (level[t] < 0) return fl; iter.assign(n, 0); T f; while ((f = dfs(s, t, inf)) > 0) fl += f; } } }; int main() { INT(n); vvi G = graph(n, n - 1); vi a, b; auto dfs = [&](auto &dfs, int u, int p, int d) -> void { if (d % 2 == 0) a.pb(u); else b.pb(u); for (int v : G[u]) { if (v == p) continue; dfs(dfs, v, u, d + 1); } }; dfs(dfs, 0, -1, 0); dinic fl(n + 2); int s = n, t = n + 1; for (int i : a) { fl.add_edge(s, i, 1); for (int j : G[i]) fl.add_edge(i, j, 1); } for (int i : b) fl.add_edge(i, t, 1); print(fl.max_flow(s, t)); }