<?php

$handle = fopen ("php://stdin","r");
$h_temp = fgets($handle);
$h = explode(" ",$h_temp);
array_walk($h,'intval');
fscanf($handle,"%s",$word);

$max = 0;

for($i=0;$i<strlen($word);$i++)
{
	$char = $word[$i];
	$height = $h[ord($char)-97];
	if ($height > $max)
		$max = $height;
}

echo $max * strlen($word);

//print_r($h);