newcommand{quickcharcount}[1]{%
immediatewrite18{texcount -1 -sum -merge -char #1.tex > #1-chars.sum }%
input{#1-chars.sum}%
}

newcommand{quickwordcount}[1]{%
immediatewrite18{texcount -1 -sum -merge #1.tex > #1-words.sum }%
input{#1-words.sum}%
}

numexpr quickwordcount{main} + quickcharcount{main}