Question
Find XOR Prime Pair
Alex is given a non-negative integer A, and his friend Ravi challenges him to find another non-negative integer B such that the XOR of A and B results in an even prime number. In other words, the result of A XOR B should yield an even prime. Can you help Alex determine such an integer B?
Input
The first and the only line of the input contains a single non-negative integer A.
Constraints
0 ≤ A ≤ 1018
Constraints
0 ≤ A ≤ 1018
Output
Print the value of B.
Example
Sample Input
10
Sample Output
8
10
Sample Output
8