I'd figure it was somewhere in the Diet building, though I'm not certain if that stands true now. [He gives a briefly perplexed look to the glasses and hair tie before sliding the glasses onto his face (they look sincerely ridiculous) and finger-combing his hair to pull it back. It's only long enough for something of a rat tail at the base of his neck, but it's passably different enough. He still wants a hat, solely for the specific color of his hair and the fact that none of these shadow people share it.]

[He gives Akira a vaguely appraising look for his attempted hair styling, and then strikes back out onto the street.] Somewhere underground would be my next best guess-- especially once they understood more of Mementos.