Presence of Mind HUD

I'm naturally loving the Presence of Mind rune on Kassadin. It's fun as hell and makes him a teamfighting monster (insert KASSAWWIIIIIIIN meme here). However, I'm either blind or there's nothing to indicate how much Presence of Mind time you actually have left on the toolbar. I feel like this is a pretty simple issue to fix and is kind of important as, especially on Kassadin, the millisecond difference between getting a free 800 mana Riftwalk and actually spending that mana can mean the difference between popping off or going OOM and being useless. Just my thoughts.