#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 heights[26];
    for(int i=0;i<26;i++) cin>>heights[i];
    string s;
    cin>>s;
    int max=0;
    for(auto a:s){
        if(heights[a-'a']>max) max=heights[a-'a'];
    }
    cout<<s.size()*max;
    return 0;
}