#include <iostream>
#include <map>

using namespace std;


int main()
{
    map<char,int> letters;
    for (int x=0; x<26; x++)
    {
        int temp;
        cin >> temp;
        letters[97+x] = temp;
    }
    string word;
    cin >> word;
    int height(0);
    for (int x=0; x<word.size(); x++)
    {
        int temp;
        temp = letters[word.at(x)];
        if (temp > height)
            height = temp;
    }

    cout << height * word.size() << endl;
    return 0;
}