How many non-attacking knights K(n) can be placed on an n x n chessboard.
Recall that a knight can attack another knight if their vertical distance on the chessboard is 2 and their horizontal distance is 1, or if their vertical distance is 1 and their horizontal distance is 2. Only one knight may be placed on each square of the chessboard.

Example 1:
Input:
n = 3
Output:
5
Explanation:
We can place 5 non-attacking knights
on a 3*3 chessboard.
Example 2:
Input:
n = 1
Output:
1
Explanation:
There is only one cell available and
we can place a knight on it.

Your Task:
You don't need to read input or print anything. Your task is to complete the function saveKnights() which takes an Integer n as input and returns the maximum number of non-attacking Knights thatr can be placed on a n*n chessboard.

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

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

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