#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() 
{
    int a[26];
    for(int i = 0;i < 26 ;i++)
        cin >>  a[i];
    string s;
    cin >> s;
    int max = 0;
    for(int i=0;i<s.size();i++)
    {
        int x = a[s[i]-'a'];
        if(x>max)
            max = x;
    }
    cout << s.size()*max <<'\n';
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}