Given a string S and you need to check whether S contains two non overlapping substrings "XY" and "YX" in any order or not.
Note : All letters of the String are Uppercased.

Example 1:
Input:
S = "XYYX"
Output:
YES
Explanation:
From stated input string "XY"
substring(1,2) and "YX" substring(3,4)
can be easily separated without overlap.
So output is "YES".
Example 2:
Input:
S = "XYX"
Output:
NO
Explanation:
"XY" and "YX" substrings are present.
But they overlap with each other.
So, Output is "NO".

Your Task:
You don't need to read input or print anything. Your task is to complete the function overlapPresent() which takes a String S and returns the answer.

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

Constraints:
1 <= |S| <= 10^{5}

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