The hashbang line is your problem; !#/usr/bin/perl should be #!/usr/bin/perl. The way you wrote it, "/usr/bin/perl" is interpreted as a comment, and the ! becomes an operator applied to the next line:

!%words = qw(...);
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And obviously that's not valid Perl.

Since you're new to Perl, here's some general tips as well: format your script nice and readable, and use strict; and use warnings; to catch many common mistakes, typos and so on.