\documentclass[a4paper, 11pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[russian]{babel}
\usepackage{amsmath, amssymb, amsfonts, amsthm}
\textheight = 23.5 cm
\textwidth = 16.5 cm
\hoffset = -2cm
\voffset = -2cm
\tolerance = 4000
\begin{document}
\renewcommand{\le}{\leqslant}
\renewcommand{\ge}{\geqslant}
\renewcommand{\epsilon}{\varepsilon}
\newcommand{\N}{\mathbb{N}}
\newcommand{\Z}{\mathbb{Z}}
\newcommand{\Q}{\mathbb{Q}}
\newcommand{\R}{\mathbb{R}}
\newcommand{\Cx}{\mathbb{C}}
\newcommand{\Zm}[1]{\mathbb{Z}_{#1}}
\newcommand{\A}{~\forall}
\newcommand{\E}{~\exists}
\theoremstyle{plain}
\title{data}
\author{data}
\maketitle
\end{document}