unicodeImport this package at the beginning of the file to instruct
LaTeX to accept unicode (UTF-8) standardized international
characters. You will also need to set up LaTeX support for
unicode by unpacking in your LaTeX source directory
(e.g. /usr/share/texmf/tex/latex) the file
http://www.unruh.de/DniQ/latex/unicode/unicode.tgz
and then running the command
texhash
To use cyrillic fonts, you will need to change the font encoding:
import unicode;
texpreamble("\usepackage{mathtext} \usepackage[russian]{babel}");
defaultpen(font("T2A","cmr"));