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


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