#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MP make_pair
#define vi vector<int>
#define vll vector<ll>
const ll MAX = 20000002;
#define MOD 1000000007

int dig[30];
int main()
{
    //ios_base::sync_with_stdio(false);
    //cin.tie(NULL);
    for(int i=0;i<26;i++)
        cin>>dig[i];
    string s;
    cin>>s;
    int h=0;
    for(int i=0;i<s.size();i++)
    {
        h=max(h,dig[s[i]-'a']);
    }
    cout<<h*s.size()<<endl;
    return 0;
}