#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 hMax = -1; 
    unordered_map<char,int> table; 
    string s;
    char c ='a'; 
    for(int i=0; i<26; i++,c++) {
        int x; 
        cin>>x;
        table[c] = x;
    } 
    cin>>s;
    int len = s.length(); 
    for(int i=0; i<len; i++) 
        hMax = max(hMax,table[s[i]]);
    cout<<(hMax*len)<<"\n"; 
    return 0;
}