You could find that out easily by printing the contents of hash %count (use Data::Dumper for that, see my additions to your script). If that isn't enough you could then change your test data and observe what is changed in the output

use Data::Dumper;

@arr=qw(19205134 18630215 18453487 18416242 18338715 18227590 17698645
+);

@arr1=qw(18227590 18053561 17698645 16966777);

foreach $e (@arr, @arr1) { $count{$e}++ }

print Dumper(\%count);
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