package main import ( "bufio" "fmt" "os" "strconv" ) func configure(scanner *bufio.Scanner) { scanner.Split(bufio.ScanWords) scanner.Buffer(make([]byte, 1000005), 1000005) } func getNextString(scanner *bufio.Scanner) string { scanned := scanner.Scan() if !scanned { panic("scan failed") } return scanner.Text() } func getNextInt(scanner *bufio.Scanner) int { i, _ := strconv.Atoi(getNextString(scanner)) return i } func getNextInt64(scanner *bufio.Scanner) int64 { i, _ := strconv.ParseInt(getNextString(scanner), 10, 64) return i } func getNextFloat64(scanner *bufio.Scanner) float64 { i, _ := strconv.ParseFloat(getNextString(scanner), 64) return i } func main() { fp := os.Stdin wfp := os.Stdout extra := 0 if os.Getenv("I") == "IronMan" { fp, _ = os.Open(os.Getenv("END_GAME")) extra = 100 } scanner := bufio.NewScanner(fp) configure(scanner) writer := bufio.NewWriter(wfp) defer func() { r := recover() if r != nil { fmt.Fprintln(writer, r) } writer.Flush() }() solve(scanner, writer) for i := 0; i < extra; i++ { fmt.Fprintln(writer, "-----------------------------------") solve(scanner, writer) } } func solve(scanner *bufio.Scanner, writer *bufio.Writer) { n := getNextInt(scanner) g := newGraph(n) for i := 0; i < n-1; i++ { u := getNextInt(scanner) - 1 v := getNextInt(scanner) - 1 g.appendEdge(u, v, i) g.appendEdge(v, u, i) } g.dfs(0, -1) fmt.Fprintln(writer, max(g.v[0].dp[0], g.v[0].dp[1])) } type vertex struct { dp [2]int } type edge struct { to, id int } type graph struct { v []vertex e [][]edge } func newGraph(n int) graph { return graph{ v: make([]vertex, n), e: make([][]edge, n), } } func (g *graph) appendEdge(from, to, id int) { g.e[from] = append(g.e[from], edge{ to: to, id: id, }) } func (g *graph) dfs(i, p int) { g.v[i].dp[1] = 1 for _, e := range g.e[i] { if e.to == p { continue } g.dfs(e.to, i) g.v[i].dp[0] += max(g.v[e.to].dp[0], g.v[e.to].dp[1]) g.v[i].dp[1] += max(g.v[e.to].dp[0], g.v[e.to].dp[1]-1) } } func max(a, b int) int { if a < b { return b } return a }