#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() 
{    long long i,c[100],z,x;
 string s;   
 for(i=0;i<26;i++)
    {
        cin>>x;
        c[i]=x;
    }
    cin>>s;
 z=0;
    for(i=0;i<s.length();i++)
        {
        z=max(z,c[s[i]-'a']);
    }
    cout<<z*s.length()<<"\n";
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}