#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 i,l,j,ma=0;
    int h[26];
    string s;
    for(i=0;i<26;i++){
        cin>>h[i];
    }
    cin>>s;
    l=s.length();
    for(i=0;i<l;i++){
        j=s[i]-97;
        ma=max(ma,h[j]);
    }
    cout<<l*ma;
    return 0;
}