use strict;
use warnings;

my %hash;
my $data = "BIN COUNT 1 20 2 0 2 1 3 0 3 0 3 1 7 0 8 2 9 1 9 2 10 3";
$hash{$1} += $2 while $data =~ /(\d+) (\d+)/g;
print "BIN COUNT ";
print "$_ $hash{$_} " for sort {$a<=>$b} keys %hash;