package main

import (
	"bufio"
	"os"
	"strconv"
	"strings"
	"fmt"
)

var s = bufio.NewScanner(os.Stdin)

func next() string {
	s.Split(bufio.ScanWords)
	s.Scan()
	return s.Text()
}
func nextLine() string {
	s.Split(bufio.ScanLines)
	s.Scan()
	return s.Text()
}

func nextInt() int {
	i, e := strconv.Atoi(next())
	if e != nil {
		panic(e)
	}
	return i
}
func nextLong() int64 {
	i, e := strconv.ParseInt(next(), 10, 64)
	if e != nil {
		panic(e)
	}
	return i
}

func mapToString(arr []int) []string {
	ret := make([]string, len(arr))
	for i := 0; i < len(arr); i++ {
		ret[i] = strconv.Itoa(arr[i])
	}
	return ret
}

func PrintI(args ...int) {
	fmt.Println(strings.Join(mapToString(args), " "))
}


func main() {
	N := nextInt()
	if N%2 == 0 {
		PrintI(N)
	}else {
		PrintI(N - 1)

	}

}