import java.awt.Point; import java.awt.Rectangle; import java.awt.geom.Rectangle2D; import java.io.BufferedInputStream; import java.io.IOException; import java.math.BigDecimal; import java.math.BigInteger; import java.util.*; import java.util.Map.Entry; import java.util.concurrent.ConcurrentSkipListSet; public class Main { public static final int C = 1000000007; static final int CY = 1000000000; public void calc() { StringBuilder sb = new StringBuilder(); BufferedInputStream bs = new BufferedInputStream(System.in); Scanner sc = new Scanner(bs); int n = sc.nextInt(); int ans = 0; //double ans = 0.0; ans = n + (n%2 == 1?1: 0); System.out.println(ans); } public static void main(String[] args) { Main main = new Main(); main.calc(); } }