#include <bits/stdc++.h>

using namespace std;

typedef long long LL;
typedef pair<int, int> PII;
typedef long double LD;
typedef vector<int> VI;
typedef vector<VI> VVI;

const int mod = 1000000007;

#define all(x) (x).begin(), (x).end()
#define bitCount __builtin_popcount

const int maxn = 100005;
const int inf = 1e8;

int main() {
  VI h(26);
  for (int i = 0; i < 26; ++i) {
    scanf("%d", &h[i]);
  }
  string s;
  int m = 0;
  cin >> s;
  for (auto c : s) {
    m = max(m, h[c - 'a']);
  }
  cout << m * s.size();
  return 0;
}