#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
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];
    int h=0;
    string s;
    cin>>s;
    for(int i=0;i<s.size();i++)
        h=max(h,a[s[i]-'a']);
    cout<<(s.size()*h)<<endl;
    return 0;
}