Latex File Producing a Letter for Plain Paper

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\input let-head
\address{Ding Dong\\9143 Dingaling Dr.\\El Paso, Tx 79907}
\signature{Dingie Dong\\T.A.}            
\begin{document}
\begin{letter}{Dr. Eugene F. Schuster\\Department of Mathematical
Sciences\\U.T. El Paso\\ El Paso, Tx  79968-0514}
\opening{Dear Old Schuster:}

\parindent .4in I do not agree that $\hat\pi\rightarrow 0$ under the
null hypothesis $H_o$, but feel that $\hat\pi\rightarrow 1$. I believe
$(\hat\pi-1)^2\rightarrow 0$ under the alternative $H_a$ is much more
difficult to prove.  I have enclosed my ``Scratch Notes" indicating why?

Will the second paragraph indent automatically? Yes, I guess so ({\em if
you tell it how}).

\closing {Sincerely,}
\ps{\noindent P.S. What's this stuff good for?}
%  \cc{ }
\encl{Scratch Notes.}
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