use strict;
use warnings;
use List::Util 'reduce';

sub hash_char_count {
    my $orders = shift;
    my $count  = 0;
    foreach my $order (@$orders) {
        $count += reduce { $a += length $b } 0, %$order;
    }
    return $count;
}

my $orders = [
    {
        'OrderDate'      => '2019-11-01 00:00:00',
        'AlternateKey'   => 'D',
        'Customer'       => '1238756',
        'SalesOrder'     => '10928',
        'CustomerName'   => 'Dunder Mifflin',
        'ShippingInstrs' => 'Standard'
    },
    {
        'OrderDate'      => '2020-01-15 00:00:00',
        'SalesOrder'     => '11349',
        'Customer'       => '1239451',
        'AlternateKey'   => 'R',
        'CustomerName'   => 'Vance Refrigeration',
        'ShippingInstrs' => 'Standard'
    },
    {
        'OrderDate'      => '2020-01-22 00:00:00',
        'SalesOrder'     => '12954',
        'Customer'       => '1240029',
        'AlternateKey'   => 'R',
        'CustomerName'   => 'A1A Car Wash',
        'ShippingInstrs' => 'Next Day'
    }
];

print hash_char_count($orders);