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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int a[26],l,t,i,ans,hmax=1;
    for(i=0;i<26;i++)
        cin>>a[i];
    string s;
    cin>>s;
   
   
    for(i=0;s[i]!='\0';i++)
        {
        t=s[i]-97;
        //cout<<t<<endl;
        hmax=max(hmax,a[t]);
    }
    ans=hmax*i;
    //cout<<hmax<<endl<<i;
    cout<<ans;
    return 0;
}