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);
}
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
boolean blank = false;
while (scanner.hasNextBigInteger()) {
if (blank) {
System.out.println();
} else {
blank = true;
}
BigInteger a = scanner.nextBigInteger();
BigInteger b = scanner.nextBigInteger();
System.out.println(a.gcd(b));
}
}