#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include<stdlib.h>
#include<stdio.h>

using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int a[26];
    for(int i=0;i<26;i++)
        {
        cin>>a[i];
    }
    string s;
    char f;
    //cin>>f;
    fflush(stdin);
  
    //cin.clear();
    //getch();
    cin>>f;
    //cin.ignore('\n'); 
    getline(cin,s);
    //cin>>s;
    int area=0,max=-1,count=0,ta=0;
    if(f==32)
    count=0;
    else {count=1;
          max=a[f-97];
         }
    int h=s.size();
    //cout<<"size of "<<h<<endl;
    //cout<<s<<endl;
    for(int i=0;i<=h;i++)
        {
        if(i==h||s[i]-97<0)
           {
            //cout<<"Break "<<count<<endl;
            area=count*max;
            ta+=area;
            count=0;
            max=-1;
        }
        else {if(a[s[i]-97]>max)
            max=a[s[i]-97];
        //cout<<s[i]<<" "<<i<<endl;
        count++;
        }
        //cout<<endl<<count;
    }
    cout<<endl<<ta<<endl;
    return 0;
}