#include<bits/stdc++.h>
using namespace std;
 
#define   MOD   1000000009
#define   X     first
#define   Y     second
#define   MAX   4000006
#define   sc    scanf
#define   pf    printf
#define   pb    push_back
#define   pff   push_front
#define   mp    make_pair
#define   ll    long long
 
 
 
#define iosbase  ios_base::sync_with_stdio(false)
#define dbg(x)   cout<<#x<<"="<<x<<endl
int h[30];

int main()
{
    int i;
    string str;
    int hm=-1;

    for(i=0;i<26;i++)
        cin>>h[i];
    cin>>str;
    for(i=0;i<str.length();i++)
        hm=max(hm,h[str[i]-'a']);

    cout<<hm*str.length()<<endl;
}