import java.util.Scanner;

class Input {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		while (true) {
			String inp = input.nextLine();
			if (inp.equals("end")) {
				System.exit(0);
			}
			int num = Integer.parseInt(inp);
			System.out.println(num * 2);
		}
	}
}