\input fop
%
\shipout\hbox{\smash{\hbox{\hbox{% line 25 3-5-17.mp
$I$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 26 3-5-17.mp
$\Delta I$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 27 3-5-17.mp
\Fi}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 28 3-5-17.mp
$M$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 29 3-5-17.mp
$N$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 30 3-5-17.mp
$O$}\vrule width1sp}}}
\end{document}
