#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <numeric>
#include <algorithm>
#include <functional>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <utility>
#include <cassert>
#include <iomanip>
#include <ctime>

using namespace std;

const int me = 100025;

int a[me];
string s;

int main(int argc, const char * argv[]) {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    for(int i = 0; i < 26; i ++)
        cin >> a[i];
    cin >> s;
    int l = 0;
    for(char i : s)
        l = max(l, a[i - 'a']);
    cout << (int)s.size() * l << endl;
    
    return 0;
}