#include<bits/stdc++.h>
using namespace std;

int main(){
    int n=26;
    vector<int> h(n);
    for(int h_i = 0;h_i < n;h_i++){
       cin >> h[h_i];
    }
    string word;
    cin >> word;
    
    int num = 0,ans=0;
    int i,cnt = 0,mh=0;
    for(i=0;i<word.length();i++){
        if(word[i]==' '){
            ans += cnt*mh;
            cnt = 0;
            mh = 0;
        }
        else{
            cnt++;
            mh = max(mh,h[word[i]-'a']);
        }
    }
    ans += cnt*mh;
    cout<<ans<<endl;
    return 0;
}