What happens if I put blue hair dye over green hair?

I have green hair like the one in the photo. I already posted this question but forgot to include the photo. It isn’t me but my hair color is the same as the photo.
If I put a dark blue hair dye, will it come out blue?
What happens if I put blue hair dye over green hair?
What happens if I put blue hair dye over green hair?
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