It's a great question.
It's a problem everywhere. We need to understand it in the Indo-Pacific, we need to understand it in the Arctic and we need to understand it in the approaches to North America. Part of the NORAD modernization, because the NORAD mission also has maritime domain awareness, is to look at how we increase subsurface and maritime domain awareness.
We're making investments in there. I don't have the specific data, because I wasn't expecting that question, but a portion of the $40 billion that was announced for NORAD modernization is for subsurface domain awareness around North America.