#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(){
    int h[30],max=0,count=0;
    for(int i = 0;i < 26;i++){
       cin >> h[i];
    }
    string word;
    cin >> word;
    for(int i=0;word[i]!='\0';i++){
        if(h[int(word[i])-97] > max)max=h[int(word[i])-97];
        count++;
    }
    cout<<count*max<<endl;
    return 0;
}