After a long-time thinking, I made up my mind to walk away without leaving any penny.
After a long thought, ... donating any penny.

Do both of the above sound idiomatic and mean about the same to you? Thanks.
After thinking for a long time,
After I thought for a long time,
Without donating a penny.
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Also, I consider a long thought wrong. It's not just one thought that's involved, it's a multitude of them, a process. Thought isn't process, thinking is.
Good explanation. Thanks, MH.
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Is "after long thought" a correct expression in english, whatever it means?