#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 findMax(string word, vector<int> h) {
    int max = 0;
    for(char c : word) {
        int index = (int)(c-'a');
        if(h[index] > max)
            max = h[index];
    }
    return max;
}

int main(){
    vector<int> h(26,0);
    for(int h_i = 0;h_i < 26;h_i++){
       cin >> h[h_i];
    }
    string word;
    cin >> word;
    int maxHeight = findMax(word, h);
    cout << word.length() * maxHeight << endl;
    return 0;
}