Photo of a homeless man's homemade shelter in a Tokyo park

I've been to Yoyogi Park in Tokyo many times, but I've never seen a homeless encampment there. Reditor biwook took this photo of one of the shelters there. Whoever built it did an excellent job. There's a little sign in front. I can understand three of the four kanji characters: "stand up" "enter" "???" and "stop." What does the sign say?

A homeless guy's home in Yoyogi park. Looks nicer than my apartment. from r/Tokyo

Top image: Photogra Fer/Flickr. Attribution 2.0 Generic (CC BY 2.0)