documentclass{beamer}

mode<presentation> {
usetheme{Berkeley} %FAVOURITE
}
usepackage{graphicx} % Allows including images
usepackage{booktabs} % Allows the use of toprule, midrule and bottomrule in tables
usepackage[utf8]{inputenc}
usepackage[english]{babel}
usepackage{amsmath,amsthm,verbatim,amssymb,amsfonts,amscd,graphicx}
usepackage{geometry}
usepackage{url}

%----------------------------------------------------------------------------------------
%   TITLE PAGE
%----------------------------------------------------------------------------------------

title[Display Title]{This is the Title of My Presentation} % The short title appears at the bottom of every slide, the full title is only on the title page

author[Display Author]{Mr Author} % Your name
institute[The Institute] % Your institution as it will appear on the bottom of every slide, may be shorthand to save space
{
The Institute\ % Your institution for the title page
medskip
textit{A Department} % Your email address
}
date{today} % Date, can be changed to a custom date

begin{document}

begin{frame}
titlepage % Print the title page as the first slide
end{frame}

begin{frame}
frametitle{Overview} % Table of contents slide, comment this block out to remove it
tableofcontents % Throughout your presentation, if you choose to use section{} and subsection{} commands, these will automatically be printed on this slide as an overview of your presentation
end{frame}

%----------------------------------------------------------------------------------------
%   PRESENTATION SLIDES
%----------------------------------------------------------------------------------------

%------------------------------------------------
section{Section 1 - The First Section}

section{Section 2 - 2nd Sec}
subsection{This is a sub}
%------------------------------------------------
begin{frame}
test
end{frame}
%------------------------------------------------
subsection{subtitle}
%------------------------------------------------
begin{frame}
test
end{frame}
%------------------------------------------------
subsection{A longer subsection title that overflows}
begin{frame}
test
end{frame}
subsection{A longer subsection title that overflows}
begin{frame}
test
end{frame}
subsection{A longer subsection title that overflows}
begin{frame}
test
end{frame}


section{Yet another Section}
begin{frame}
test
end{frame}
subsection{A longer subsection title that overflows}
begin{frame}
test
end{frame}
subsection{A longer subsection title that overflows}
begin{frame}
test
end{frame}

section{Too Many?}
begin{frame}
test
end{frame}
subsection{Subsection}
begin{frame}
test
end{frame}
subsection{Common Tasks}
begin{frame}
test
end{frame}

section{Too Many?}
begin{frame}
test
end{frame}
subsection{Subsection}
begin{frame}
test
end{frame}
subsection{Common Tasks}
begin{frame}
test
end{frame}