#include<bits/stdc++.h>
using namespace std;

const int INF = 1e9 , MAX = 100010;
typedef long long ll;
typedef unsigned long long LL;



int main(void)
{
    map<char, int> maping;

    int in;
    
    char x;

    for(int i=0;i<26;i++){

        cin >> in;
        
        x = 'a' + i ;
        
        maping[(char)x] = in;
    }
    //cout << maping['a'] << endl;
    string ar;
    //getline(cin , ar);
    cin >> ar;
    //cout << ar << endl;
    
    int si = ar.size();

    int hi = 0;

    for(int i=0;i < si;i++){

        if(maping[ar[i]]>hi)hi=maping[ar[i]];
    }

    cout << hi * si << endl;


    return 0;
}