#include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define INF 1000000000
#define p 1000000007
#define pb push_back
#define mp make_pair
typedef long long Int;
typedef pair<Int,Int> pii;
typedef vector<Int> vi;
typedef vector<pii> vii;
Int n,A[26];
int main()
{
    string S;
    Int h=0;
    for(Int i=0;i<26;i++)
    cin>>A[i];
    
    cin>>S;
    for(Int i=0;i<S.length();i++)
       {
        h=max(h,A[S[i]-'a']);
    }
    cout<<h*(S.length())<<endl;
    
   return 0;

}