use Data::Dumper;
while (<DATA>){
next if /^$/;
($f,$s) = split /\|/,$_;
$h{$f} += $f;
$h->{$f}{'s'} += $s;
}

for my $k (sort {$h{$b} <=> $h{$a} } keys %h){
print "Key = $k\nElement 1: $h{$k}\nElement 3: $h->{$k}{'s'}\n";
};

#print Dumper{%{$h}};
__DATA__
1|2
2|4
2|4
4|3
4|5
5|1
5|2