#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n,i,j,a[26];
    for(i=0;i<26;i++)
        {
        cin>>a[i];
    }
    string s;
    int max=-99999,ans;
    cin>>s;
    for(i=0;i<s.length();i++)
        {
        if(a[s[i]-'a']>max)
            max=a[s[i]-'a'];
    }
    ans=s.length()*max;
    cout<<ans<<endl;
}