#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <climits>
#include <map>
#include <cmath>
#include <queue>
#include <string.h>

/*
 * #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;

#define tr(container, it)  for(auto it = container.begin(); it != container.end(); it++)
#define fr(i,n) for(int i=0;i<n;i++)
#define fr1(i,j,n) for(int i=j;i<n;i++)

typedef long long ll;
typedef pair<int, int>pii;
typedef vector<int> vi;

int main (int argc, char **argv) {
//     freopen ("ct4", "r", stdin);
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 m=0;
    tr(word,it){
        m=max(m,h[*it-'a']);
    }
    cout<<m*word.size()<<endl;
    return 0;
}