#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;

int  h[26];

int main(){
    for (int i = 0; i < 26; i++)
        cin >> h[i];
    string word;
    cin >> word;
    int rr = 0;
    for (int i = 0; i < word.size(); i++)
        rr = max(rr, h[word[i] - 'a']);
    cout << rr * word.size();
    return 0;
}