#include <bits/stdc++.h>

#define F first
#define S second
#define llong long long
#define ullong unsigned long long
#define mp make_pair
#define pb push_back
#define sz(v) (int)v.size()

using namespace std;

const int MXN = (int)1e6 + 10;
const int INF = (int)1e9 + 7;
const llong LINF = (llong)1e18 + 10;
const double EPS = (double)1e-9;
const double PI = (double)acos(-1.0);

string s;
int h[MXN];

int main(){
  #ifdef LOCAL
    freopen("input.txt", "r", stdin);
  #endif // LOCAL
  for(int i = 0; i < 26; ++i){
    cin >> h[i];
  }
  cin >> s;
  int mx = 0;
  for(int i = 0; i < sz(s); ++i){
    mx = max(mx, h[s[i] - 'a']);
  }
  cout << mx * sz(s);
  return 0;
}