How do I check an item in a list of list?

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C#

LINQ

Hi,
I am new to LINQ, here is my question:
I have a List of a class, an item which is present in only one List (ItemID), and a List of List. I know how to check if the ItemID exists in the list, but I don't know how to check if the it exists in the List of List. Here is my code to check if the item exists in a list:

List<MyClass> list = new List<MyClass>;
List<List<MyClass>> Lists= new List<List<MyClass>>();
If (List.Exists(x => x.ItemID == itemIndicator.ItemID))

Please, I would like to check the ItemID in the Lists instead of List.

What I have tried:

I tried:

If (Lists.Exists(x => x.ItemID == itemIndicator.ItemID))

But it shows an error because the ItemID belongs to the list, not to the List of List.