You mean #!/usr/bin/perl

You mean do {

    if ($response eq 'yes' || 'Yes' || 'YES' || 'y') {
        $answer = $answer + 1;
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The or operators just don't work that way. You should write lc $response eq 'yes' or lc $response eq 'y' instead.

Furthermore, I don't see why you are incrementing $answer when you could just say $answer = 1