Create array of array JSON

I am trying to create a JSON that contains an array of arrays, I have looked for it, but there is no enough documentation. I have written an example below.
Have you got any idea? Thank you

{
“NN”:
[
[2.4,2.3],
[3.5,4.5]
]
}

TSharedPtr<FJsonObject> SaveData = MakeShareable(new FJsonObject);

	 TArray< TSharedPtr<FJsonValue> > ValueArray;

	 TArray< TSharedPtr<FJsonValue> > ValueArray2;
 
	 // Create two values and add them to the array
	 TSharedPtr<FJsonValue> Value1 = MakeShareable(new FJsonValueNumber(4.34));    
	 ValueArray2.Add(Value1);    
	 TSharedPtr<FJsonValue> Value2 = MakeShareable(new FJsonValueNumber(4.34));    
	 ValueArray2.Add(Value2);

	 ValueArray.Add(ValueArray2); // Error
	 ValueArray.Add(ValueArray2); // Error
 
         SaveData->SetArrayField("NN", ValueArray);