// URL: https://yukicoder.me/problems/no/763 import std.algorithm, std.array, std.container, std.math, std.range, std.typecons, std.string; version(unittest) {} else void main() { int N; io.getV(N); auto g = Graph(N); foreach (_; 0..N-1) { int U, V; io.getV(U, V); --U; --V; g.addEdgeB(U, V); } auto t = g.tree(0); auto a = new int[](N), b = new int[](N); foreach_reverse (u; t.dfsOrder) { a[u] = 1; foreach (v; t.children(u)) { a[u] += max(a[v]-1, b[v]); b[u] += max(a[v], b[v]); } } io.put(max(a[0], b[0])); } struct Graph { alias Node = int; Node n; Node[][] g; alias g this; this(Node n) { this.n = n; g = new Node[][](n); } void addEdge(Node u, Node v) { g[u] ~= v; } void addEdgeB(Node u, Node v) { g[u] ~= v; g[v] ~= u; } } struct GraphW(W = int, W i = 10^^9) { alias Node = int, Wt = W, inf = i; struct Edge { Node src, dst; Wt wt; alias cap = wt; } Node n; Edge[][] g; alias g this; this(Node n) { this.n = n; g = new Edge[][](n); } void addEdge(Node u, Node v, Wt w) { g[u] ~= Edge(u, v, w); } void addEdgeB(Node u, Node v, Wt w) { g[u] ~= Edge(u, v, w); g[v] ~= Edge(v, u, w); } } struct GraphM(W = int, W i = 10^^9) { alias Node = int, Wt = W, inf = i; Node n; Wt[][] g; alias g this; this(int n) { this.n = n; g = new Wt[][](n, n); } static GraphM!(W, i) init(Node n) { auto g = GraphM!(W, i)(n); foreach (i; 0..n) { g[i][] = inf; g[i][i] = 0; } return g; } } struct Tree(Graph) { alias Node = Graph.Node; Graph g; alias g this; Node root; Node[] parent; Node[] dfsOrder; int[] size; int[] depth; this(Graph g, Node r) { this.g = g; this.root = r; parent = new Node[](n); depth = new int[](n); depth[] = -1; struct UP { Node u, p; } auto st = SList!UP(UP(r, r)); while (!st.empty) { auto up = st.front; st.removeFront(); parent[up.u] = up.p; depth[up.u] = depth[up.p] + 1; dfsOrder ~= up.u; foreach (v; g[up.u]) if (v != up.p) st.insertFront(UP(v, up.u)); } size = new int[](n); size[] = 1; foreach_reverse (u; dfsOrder.drop(1)) size[parent[u]] += size[u]; } pure auto children(Node u) { return g[u].filter!(v => v != parent[u]); } } Tree!Graph tree(Graph, Node)(Graph g, Node r) { return Tree!Graph(g, r); } auto io = IO!()(); import std.stdio; struct IO(alias IN = stdin, alias OUT = stdout) { import std.conv, std.format, std.meta, std.traits, core.stdc.stdlib; auto getV(T...)(ref T v) { foreach (ref w; v) get(w); } auto getA(T)(size_t n, ref T v) if (hasAssignableElements!T) { v = new T(n); foreach (ref w; v) get(w); } auto getC(T...)(size_t n, ref T v) if (allSatisfy!(hasAssignableElements, T)) { foreach (ref w; v) w = new typeof(w)(n); foreach (i; 0..n) foreach (ref w; v) get(w[i]); } auto getM(T)(size_t r, size_t c, ref T v) if (hasAssignableElements!T && hasAssignableElements!(ElementType!T)) { v = new T(r); foreach (ref w; v) getA(c, w); } template getS(E...) { auto getS(T)(size_t n, ref T v) { v = new T(n); foreach (ref w; v) foreach (e; E) mixin("get(w."~e~");"); } } const struct PutConf { bool newline = true, flush, exit; string floatFormat = "%.10f", delimiter = " "; } auto put(alias conf = "{}", T...)(T v) { mixin("const PutConf c = "~conf~"; putMain!c(v);"); } auto putB(alias conf = "{}", S, T)(bool c, S t, T f) { if (c) put(t); else put(f); } auto putRaw(T...)(T v) { OUT.write(v); OUT.writeln; } private { dchar[] buf; auto sp = (new dchar[](0)).splitter; void nextLine() { IN.readln(buf); sp = buf.splitter; } auto get(T)(ref T v) { if (sp.empty) nextLine(); v = sp.front.to!T; sp.popFront(); } auto putMain(PutConf c, T...)(T v) { foreach (i, w; v) { putOne!c(w); if (i < v.length-1) OUT.write(c.delimiter); } static if (c.newline) OUT.writeln; static if (c.flush) OUT.flush(); static if (c.exit) exit(0); } auto putOne(PutConf c, T)(T v) { static if (isInputRange!T && !isSomeString!T) putRange!c(v); else if (isFloatingPoint!T) OUT.write(format(c.floatFormat, v)); else OUT.write(v); } auto putRange(PutConf c, T)(T v) { auto w = v; while (!w.empty) { putOne!c(w.front); w.popFront(); if (!w.empty) OUT.write(c.delimiter); } } } }