Customizing jepack’s related posts on mobile device

functions.php

function jetpackme_more_related_posts( $options ) {
if(wp_is_mobile()):
$options['size'] = 2;
else:
$options['size'] = 3;
endif;
return $options;
}
add_filter( 'jetpack_relatedposts_filter_options', 'jetpackme_more_related_posts' );