You can adjust the .15ex if you wish to change the distance between the stacked lines. In this MWE, the symbol is made to fit to 1.95ex in vertical extent, which can also be adjusted.
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[russian,english]{babel}
\usepackage{scalerel,tabstackengine,graphicx}
\def\mysym{\foreignlanguage{russian}{%
\setstackgap{S}{.15ex}\scaleto{$\tabbedShortstack{п&м\\п&у}$}{1.95ex}}}
\def\test{a\mysym b}
\begin{document}
{\Large\test}\par\test\par{\footnotesize\test}
\end{document}

And if one prefers the symbol in bold, as the OP's graphic might indicate, a one-word change to the MWE accomplishes that:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[russian,english]{babel}
\usepackage{scalerel,tabstackengine,graphicx}
\def\mysym{\foreignlanguage{russian}{%
\setstackgap{S}{.15ex}\scaleto{$\bfseries\tabbedShortstack{п&м\\п&у}$}{1.95ex}}}
\def\test{a\mysym b}
\begin{document}
{\Large\test}\par\test\par{\footnotesize\test}
\end{document}

stackengineprobably. – percusse Mar 18 '14 at 05:54\shortstack{<top>\\<bottom>}.... (Which is not to say thatstackengineis pretty awesome.) – jon Mar 18 '14 at 06:08