#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 main(){
    vector<int> h(26);
    int hi;
    for(int h_i = 0;h_i < 26;h_i++){
       cin >> hi;
       h[h_i]=hi;
    }
    string word;
    cin >> word;
    int i=0;
    int mx=-1;
    for(char c: word){
        if(h[c-'a']>mx)
            mx=h[c-'a'];
    }
    cout<<mx*word.length();
    return 0;
}