This is pdfTeX, Version 3.14159265-2.6-1.40.17 (TeX Live 2017/dev) (preloaded format=pdftex 2017.3.9)  17 APR 2017 17:10
entering extended mode
 restricted \write18 enabled.
 %&-line parsing enabled.
**boxandbox1
(./boxandbox1.tex
Underfull \hbox (badness 10000) detected at line 2
\tenrm XX

\hbox(6.83331+0.0)x30.51758
.\tenrm X
.\tenrm X


Underfull \hbox (badness 10000) detected at line 4
\tenrm YY

\hbox(6.83331+0.0)x30.51758
.\tenrm Y
.\tenrm Y

[1{/usr/local/texlive/2016/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] )</us
r/local/texlive/2016/texmf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb>
Output written on boxandbox1.pdf (1 page, 8929 bytes).
PDF statistics:
 12 PDF objects out of 1000 (max. 8388607)
 7 compressed objects within 1 object stream
 0 named destinations out of 1000 (max. 500000)
 1 words of extra memory for PDF output out of 10000 (max. 10000000)