何でも
なんでも · nandemo · JLPT N3 · expression
everything
何 (what) + でも (even) = even what = whatever, anything at all
何 nan means what, and でも demo means even or any. Put together, even what becomes anything at all, or everything. Used as an answer, なんでもいい means anything is fine, which is where by all means comes from.