// https://www.hackerrank.com/contests/101hack40/challenges/designer-pdf-viewer
#include <list>
#include <iostream>
#include <iterator>
#include <algorithm>
#include <limits>
#include <cassert>
#include <cmath>
#include <map>
#include <set>
#include <chrono>
#include <cstddef>
#include <vector>
#include <iomanip>
#include <unordered_set>
#include <unordered_map>
#include <deque>
#include <queue>
#include <memory>

using namespace std;
using number_t = uint_fast64_t;

// --------------------------------------------------------------------------------

int main() {
  size_t N = 26;
  vector<number_t> v;
  v.reserve(N);
  copy_n(istream_iterator<number_t>(cin), N, back_inserter(v));

  string s;
  cin >> s;
  number_t max_h = 0;
  for (auto ch : s) {
    auto h = v[ch - 'a'];
    if (h > max_h) {
      max_h = h;
    }
  }
  cout << (max_h * s.length()) << endl;
  return 0;
}

// --------------------------------------------------------------------------------