A high school for the so-called "students in economy" (not economics!), i.e. the plumbers, masons, sheet metal workers (a limar by any other name), cooks, waiters, weavers, tailors, wall painters etc. Škola učenika u privredi, ŠUP, was frequently called Škola umno poremećenih (school for mentally disturbed), or šupa (shed).
I worked there for one semester, and then in, I guess, 1984, took one or two classes there to get paid a bit extra, which was a nightmare of a schedule, and I forgot to go there at least once. Luckily, after a couple of months they found some better arrangement. Still, one girl from that class remembers me, and she's a butcher in a shop in the community center near Springfield.
For a while they had a kickout division in Perlez, where, technically, I did the first official workday of my life.