#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 h[26], i, maximum =-1e9;
    string s;
    for(i =0;i<26;++i)
        cin>>h[i];
    cin>>s;
    for(i =0;i<s.size();++i)
        maximum =max(maximum, h[s[i]-'a']);
    cout<<s.size()*maximum;
    return 0;
}