public static void main(String[] args) {
Scanner in = new Scanner(System.in);
while (in.hasNextBigInteger()) {
BigInteger N = in.nextBigInteger();
if (N.compareTo(BigInteger.ONE) > 0) {
BigInteger two = new BigInteger("2");
N = N.multiply(two).subtract(two);
}
System.out.println(N);
}
}