#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int main(){
    int n = 26;
    int *h = malloc(sizeof(int) * n);
    for(int h_i = 0; h_i < n; h_i++){
       scanf("%d",&h[h_i]);
    }
    char* word = (char *)malloc(512000 * sizeof(char));
    scanf("%s",word);
    int result;
    int totalwidth = strlen(word);
    int totalheight = 0;
    int value;
    int num;
    for (int i = 0; i < strlen(word); i++) {
        num = word[i] - 'a';
        value = h[num];
        if (value > totalheight)
            totalheight = value;
    }

    
    result = totalwidth * totalheight;
    printf("%d\n",result);
    return 0;
}