#!usr/bin/perl

use strict;
use warnings;

use Data::Dumper;
use List::Util qw/sum/;

my $rows = [
    [1, 2, 3],
    [1, 2, 3],
    [1, 2, 3],
];

my @row_sum = map { sum @$_ } @$rows;
print Dumper \@row_sum;

my $total_sum = sum @row_sum;
print $total_sum . "\n";