import java.util.*;
import java.io.*;

public class A {
	public static void main(String[] args) {
		new A().solve();
	}

	FasterScanner in = new FasterScanner();
	PrintWriter out = new PrintWriter(System.out);

	long mod = (long) 1e9 + 7;

	public void solve() {
		// int tt=in.nextInt();
		// for(int ii=0;ii<tt;ii++)
		{
			int[] arr = in.nextIntArray(26);
			String str = in.nextLine();
			int ans = 0;
			
			for(int i=0;i<str.length();i++) {
				ans  = Math.max(ans, arr[str.charAt(i)-'a']);
			}
			System.out.println(ans*str.length());
		}
		out.close();
	}

	Node[] g;
	ArrayList<Edge>[] t;
	int[] size;
	long[] arr;
	int n;

	void dfs(int idx) {
		int temp = 0;
		// System.out.print(" dfs " + idx);
		// for(Edge x: t[idx]) {
		// System.out.print(" "+x.next.idx);
		// }
		int sum = 1;
//		System.out.println();
		for (Edge x : t[idx]) {

			dfs(x.next.idx);

			temp = size[x.next.idx];
			sum += temp;
			arr[x.val] += temp*1l * (n - temp);
		}
		// System.out.println();
		size[idx] = sum;
	}

	class Edge {
		Node next;
		int val;

		public Edge(Node n, int val) {
			this.next = n;
			this.val = val;

		}
	}

	class Node implements Comparable<Node> {
		int idx;
		int val;
		int pa;
		ArrayList<Edge> next = new ArrayList<>();

		public Node(int idx) {
			this.idx = idx;
			this.val = Integer.MAX_VALUE;
		}

		public int compareTo(Node o) {
			if (this.val != o.val)
				return Integer.compare(this.val, o.val);
			return Integer.compare(this.idx, o.idx);
		}
	}

	public static class FasterScanner {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

		public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		private boolean isSpaceChar(int c) {
			return c == '\n' || c == '\r' || c == -1 || c == ' ' || c == '\t';
		}

		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}

			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public double nextDouble() {
			return Double.parseDouble(nextString());
		}

		public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public int[] nextIntArray10(int n) {
			int[] arr = new int[n + 1];
			for (int i = 1; i <= n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray10(int n) {
			long[] arr = new long[n + 1];
			for (int i = 1; i <= n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public int[] nextIntArray11(int n) {
			int[] arr = new int[n + 2];
			for (int i = 1; i <= n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray11(int n) {
			long[] arr = new long[n + 2];
			for (int i = 1; i <= n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}
	}

}