Otta, Elias, and Hans measured the lengths of their ladders. \begin{tabular}{|c|c|}
\hline
Friend & Ladder length \\
\hline
Otta & 23 m \\
Elias & 47 m \\
Hans & 29 m \\
\hline
\end{tabular} What is the length of Elias and Hans' ladders combined?