#!/usr/bin/perl -w

use strict;

my @array = qw(
1    info    
1    info
1    info
2    info
3    info
3    info
4    info
4    info
4    info
4    info
);

my %score;
for (my $i=0;$i<$#array;$i+=2) { # get numbers from @array
    $score{ $array[$i] }++;                # count the numbers
}

my %infos =  @array;

my @output =
    map  { "$_\t$infos{$_}\n"; }
    sort { $score{$b} <=> $score{$a} }
    keys %score;
    
print @output;