#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 n, x;

int main(){
    vector<int> h;
    for(int h_i = 0;h_i < 26;h_i++){
       cin >> x;
       h.push_back(x);
      
    }
    string word;
    cin >> word;
  
    int temp = 0;
    for(int i = 0; i < word.size(); i++){
        int t = word[i] - 'a';
        
        temp = max(temp, h[t]);
    }
    
    
   cout << temp * word.size() << endl;
    return 0;
}