#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define pii pair<int,int>
#define LL long long
#define st first
#define nd second
using namespace std;
int a[26],mx=0;
string b;
int main(){
    for(int i=0;i<26;++i)
        cin>>a[i];
    cin>>b;
    for(int i=0;i<b.size();++i)
        mx=max(mx,a[b[i]-'a']);
    cout<<mx*b.size()<<endl;
}