#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;
map<char,int> mp ;

int main(){
    vector<int> h(26);
    for(int i = 0;i < 26;i++){
       cin >> h[i];
       mp['a'+i] =h[i] ;
    }
    string word;
    cin >> word;
    int n=word.length() ;
    int mx= -1000000101;
    for (int i=0;i<n;i++) {
        mx=max(mx,mp[word[i]]) ;
 
    }
    cout <<mx*n<<"\n" ;
    return 0;
}