This is pdfTeX, Version 3.14159265-2.6-1.40.16 (TeX Live 2015/Debian) (preloaded format=pdflatex 2017.8.31)  16 SEP 2018 14:18
entering extended mode
 restricted \write18 enabled.
 %&-line parsing enabled.
**preamble.tex
(./preamble.tex
LaTeX2e <2016/02/01>
Babel <3.9q> and hyphenation patterns for 81 language(s) loaded.

! LaTeX Error: \usepackage before \documentclass.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.1 \usepackage[utf8]{
                      inputenc}
\usepackage may only appear in the document preamble, i.e.,
between \documentclass and \begin{document}.


! LaTeX Error: \usepackage before \documentclass.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.2 \usepackage{
                color}
\usepackage may only appear in the document preamble, i.e.,
between \documentclass and \begin{document}.


! LaTeX Error: \usepackage before \documentclass.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.3 \usepackage{
                amsmath}
\usepackage may only appear in the document preamble, i.e.,
between \documentclass and \begin{document}.

! Undefined control sequence.
l.5 \DeclareMathOperator
                        *{\max}{max}
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.


! LaTeX Error: Missing \begin{document}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              
                                                  
l.5 \DeclareMathOperator*
                         {\max}{max}
You're in trouble here.  Try typing  <return>  to proceed.
If that doesn't work, type  X <return>  to quit.

Missing character: There is no * in font nullfont!
! Missing $ inserted.
<inserted text> 
                $
l.5 \DeclareMathOperator*{\max
                              }{max}
I've inserted a begin-math/end-math symbol since I think
you left one out. Proceed, with fingers crossed.

LaTeX Font Info:    External font `cmex10' loaded for size
(Font)              <7> on input line 5.
LaTeX Font Info:    External font `cmex10' loaded for size
(Font)              <5> on input line 5.
! Extra }, or forgotten $.
l.5 \DeclareMathOperator*{\max}
                               {max}
I've deleted a group-closing symbol because it seems to be
spurious, as in `$x}$'. But perhaps the } is legitimate and
you forgot something else, as in `\hbox{$x}'. In such cases
the way to recover is to insert both the forgotten and the
deleted material, e.g., by typing `I$}'.

)
! Emergency stop.
<*> preamble.tex
                
*** (job aborted, no legal \end found)

 
Here is how much of TeX's memory you used:
 7 strings out of 493029
 166 string characters out of 6136234
 53072 words of memory out of 5000000
 3643 multiletter control sequences out of 15000+600000
 3640 words of font info for 14 fonts, out of 8000000 for 9000
 1141 hyphenation exceptions out of 8191
 19i,2n,12p,63b,58s stack positions out of 5000i,500n,10000p,200000b,80000s
!  ==> Fatal error occurred, no output PDF file produced!