You are given a decimal number n. You need to find the gray code of the number n and convert it into decimal.
Gray code is a binary numeral system where two successive values differ in only one bit.
For example, the sequence of Gray codes for 3-bit numbers is: 000, 001, 011, 010, 110, 111, 101, 100, so G(4)=6.
Example 1:
Input:
n = 7
Output:
4
Explanation:
7 is represented as 111 in binary form.
The gray code of 111 is 100, in the binary
form whose decimal equivalent is 4.
Example 2:
Input:
n = 10
Output:
15
Explanation:
10 is represented as 1010 in binary form.
The gray code of 1010 is 1111, in the binary
form whose decimal equivalent is 15.

Your Task:
You don't need to read input or print anything. Your task is to complete the function getGray() which takes an Integer n as input and returns the answer.

Expected Time Complexity: O(1)
Expected Auxiliary Space: O(1)

Constraints:
0 <= n <= 10^{8}

见题面

见题面