Given the menu of the two restaurants. There may be a chance of fight between them if any one of them have any item in common and you surely don't want that to happen. Each of the menu has 5 items (strings) in them. So, your task is to find out if there is any need to change the menu or let them be happy with their respective menu.

Example 1:
Input:
cake pastry fish candy meat
burger ham fish cake sauce
Output:
CHANGE
Explanation:
"fish" is common in both the menu.
Example 2:
Input:
pizza chicken cake chilli candy
choco coco cabbage panner cheese
Output:
BEHAPPY
Expanation:
No item is common.

Your Task:
You don't need to read or print anything. Your task is to complete the function is_common() which takes first menu as first parameter and second menu as second parameter and returns the string "CHANGE" if any item is common otherwise returns "BEHAPPY"(Without quotes).

Expected Time Complexity: O(n)
Expected Space Complexity: O(n)

Constraints:
1 <= Size of each string <= 1000

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