#include<bits/stdc++.h>
#define F first
#define S second
#define tr(v,it) for(auto it=v.begin();it!=v.end();it++)
#define pb push_back
#define mp make_pair
using namespace std;
int main()
{
//freopen("input.txt","r",stdin);
vector<long long>v(26);
    int n=26;
for(int i=0;i<n;i++)
cin>>v[i];
string s;
cin>>s;
long long h=-1;
for(int i=0;i<s.size();i++)
{
  h=max(v[s[i]-'a'],h);
}
cout<<s.size()*h;

  return 0;
}