By my second trip, I had learnt more or less how to read the kana, though sometimes it was a crossword-puzzle approach. I also knew the kanji for 女, thanks to
japanese.stackexchange.com/questions/4404/…女-toくノ一 . During the trip, I got the hang of the kanji for male, and for big and small. Enough kanji to go to the toilet and choose the correct flush!