import java.io.*; import java.util.*; import java.text.*; import java.math.*; import java.util.regex.*; public class Solution { public static void main(String[] args) throws IOException { Scanner in = new Scanner(System.in); int[] heights = new int[26]; for (int i = 0; i < 26; i++) { heights[i] = in.nextInt(); } char[] s = in.next().toCharArray(); int max = -1; for (char c : s) { max = Math.max(heights[c-'a'], max); } System.out.print(max * s.length); } }