#include<bits/stdc++.h>
#define rep(i, begin, end) for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))
#define eb emplace_back
#define pb push_back
#define ll unsigned long long
#define mp make_pair
#define x first
#define y second
#define mod 1000000007
#define min(a,b) a<b?a:b
#define max(a,b) a>b?a:b
#define sc(a) scanf("%d",&a);
using namespace std;

int gcd(int a,int b)
{
    if(b==0)
        return a;
    else return gcd(b,a%b);
}
int main()
{
  int a[26];
  int i;
  rep(i,0,26) 
    cin >> a[i];
  string s;
  cin >> s;
  int ans=0;
  rep(i,0,s.size())
    ans=max(ans,a[s[i]-'a']);
  cout << (ans*s.size());
  return 0;

}