exam.pdf: exam.dvi
	dvips -f < $< | ps2pdf - > $@

exam.dvi: exam.tex first.tex second.tex third.tex img/1c.eps
	latex $<
	latex $<

img/%.eps: img/%.dot
	dot -Teps < $< > $@

clean:
	$(RM) -v $(addprefix exam.,pdf aux log dvi)