/*
	 * Developer: Mihir Shah
	 * Email: mihirsmi404@gmail.com
	*/
	#include <stdio.h>
	#include <limits.h>
	#include <string.h>
	#include <math.h>
	#include <stdlib.h>
	#define si(n) scanf("%d", &n);
	#define sl(n) scanf("%ld", &n);
	#define sll(n) scanf("%lld", &n);
	#define pi(n) printf("%d\n", n);
	#define pl(n) printf("%ld", n);
	#define pll(n) printf("%lld", n);
	/*
	 * This code is implementation of Merge Sort in C
	 * This code is O(nlogn) in time complexity
	 * Each recursive call needs O(n) auxillary space
	 * This code can also be used to count number of inversions in given input array
	*/

	void initializeArray(int arr[], int value, int size)
	{
		int i;
		for(i = 0; i < size; i++)
			arr[i] = value;
		return;
	}

	void printArrayNewLine(int arr[], int size)
	{
		int i;
		for(int i = 0; i < size; i++)
			pi(arr[i]);
	}

	void printArraySpace(int arr[], int size)
	{
		int i;
		for(i = 0; i < size; i++)
			printf("%d ", arr[i]);
		printf("\n");
	}

	void mergeSort(int arr[], int low, int high)
	{
		if(low == high)
			return;

		int mid,i;
		mid = (low + high) / 2;

		mergeSort(arr, low, mid);
		mergeSort(arr, mid + 1, high);

		int tempArray[high - low + 1];
		int key1 = low, key2 = mid + 1;
		int size = (high - low + 1);

		//Storing sorted version in temporary array
		for(i = 0; i < size; i++)
		{
			if(key1 == mid + 1)
			{
				if(key2 != high + 1)
				{
					tempArray[i] = arr[key2];
					key2++;
				}
			}

			else if(key2 == high + 1)
			{
				if(key1 != mid + 1)
				{
					tempArray[i] = arr[key1];
					key1++;
				}
			}

			else
			{
				if(arr[key1] < arr[key2])
				{
					tempArray[i] = arr[key1];
					key1++;
				}

				else
				{
					tempArray[i] = arr[key2];
					key2++;
				}
			}
		}	
		//Now storing sorted array in main array
		for(i = low; i <= high; i++)
		{
			arr[i] = tempArray[i - low];
		}
		return;
		
	}

	int binarySearch(int arr[], int low, int high, int value)
	{
		if(high >= low)
		{
			int mid = (low + high) / 2;
			if(arr[mid] == value)
				return mid;
			if(arr[mid] < value)
				return binarySearch(arr, mid + 1, high, value);
			return binarySearch(arr, low, mid - 1, value);
		} 
		return -1;
	}

	//Main

	int main()
	{
		int arr[26];
		initializeArray(arr, 0, 26);
		char str[20];
		for(int i =0; i < 26; i++)
			si(arr[i]);
		scanf("%s",str);
		int l = strlen(str);
		int answer = l;
		int max = 0;
		for(int i = 0; i < l; i++)
		{
			int index = str[i] - 'a';
			if(arr[index] > max)
				max = arr[index];
		}
		pi(answer * max);
		return 0;
	}