use strict;
use warnings;

my @AoA = ( [ 'Jan', 10, 20 ], [ 'Feb', 15, 25 ], [ 'Mar', 30, 33 ] );

my @column;
for my $month_data (@AoA) {
  push @column, $month_data->[0];
}
print join( ' ', @column ), "\n";