#include "bits/stdc++.h"
#define wsp                cin >> ws;
#define sp                 setprecision
#define sz                 size()
#define sn(n)              scanf("%lld",&n)
#define cn(n)              cin>>n
#define pr(n)              printf("%lld\n",n)
#define ff                 first
#define ss                 second
#define pry                cout<<"Yes"<<endl
#define prn                cout<<"No"<<endl
#define str(n)             scanf("%s",n)
#define pb                 push_back
#define len(n)             n.length()
#define forp(i,a,b)        for(ll i=a;i<=b;i++)
#define rep(i,n)           forp(i,0,n-1)
#define ren(i,n)           for(ll i=n-1;i>=0;i--)
#define forn(i,a,b)        for(ll i=a;i>=b;i--)
#define all(n)             n.begin(),n.end()
#define alll(n,i,j)        n.begin()+i,n.begin()+j
#define present(s,x)       (s.find(x) != s.end()) 
#define cpresent(s,x)      (find(all(s),x) != s.end()) 
#define LALIT              ios_base::sync_with_stdio(false);cin.tie(0)
#define tr(container, it)  for(__typeof(container.begin()) it = container.begin(); it != container.end(); it++)
#define mem(n,m)           memset(n,m,sizeof(n))
#define mp                 make_pair
#define mod                1000000007                                                                             
#define E                  1e-9
#define PI                 3.14159265358979323846
#define N                  300005
using namespace std;
typedef unsigned long long int ull;
typedef long long int          ll;
typedef pair<int, int>         i_i;
typedef pair<ll, int>          ll_i;
typedef pair<double, int>      d_i;
typedef pair<ll, ll>           ll_ll;
typedef pair<double, double>   d_d;
 /*
template<typename T,typename T1>
void prin(vector<pair<T,T1> >& a)
{
    for(int i=0;i<a.size();i++)
    {
        cout << a[i].fi<<" "<<a[i].se<<"\n";
    }
}
 
template<typename T>
void prin(vector<T>& a)
{
    for(int i=0;i<a.size();i++)
    {
        cout << a[i];
        if(i<a.size()-1)
            cout<<" ";
        else
            cout <<"\n";
    }
}
 
 
template<typename T>
void prin_new_line(vector<T>& a)
{
    for(int i=0;i<a.size();i++)
    {
        cout << a[i]<<"\n";
    }
}
 
template<typename T,typename T1>
void prin_new_line(vector<pair<T,T1> >& a)
{
    for(int i=0;i<a.size();i++)
    {
        cout << a[i].fi<<" "<<a[i].se<<"\n";
    }
}
 
int sum_vec(vector<int>& a)
{
    int s=0;
    for(int i=0;i<a.size();i++)
    {
        s+=a[i];
    }
    return s;
}
 
template<typename T>
T max(vector<T>& a)
{
    T ans=a[0];
    for(int i=1;i<a.size();i++)
    {
        ans=max(ans,a[i]);
    }
    return ans;
}
 
template<typename T>
T min(vector<T>& a)
{
    T ans=a[0];
    for(int i=1;i<a.size();i++)
    {
        ans=min(ans,a[i]);
    }
    return ans;
}
 
template<typename T>
T min(T a,T b,T c)
{
    return min(a,min(b,c));
}
 
template<typename T>
T max(T a,T b,T c)
{
    return max(a,max(b,c));
}
 
long double s_triangle(long double x1,long double y1,long double x2,long double y2,long double x3,long double y3)
{
    return abs(((x2-x1)*(y3-y1)-(x3-x1)*(y2-y1))/2);
}
 
bool overflow(ll a,ll b)
{
    if(a*b/b!=a)
        return true;
    return false;
}
*/
ll n = 26, k , l , t , j , cnt;

ll a[N] ,b[N];

int main(){
     LALIT;
     vector<int> h(n);
     int m = 0;
    for(int h_i = 0;h_i < n;h_i++){
       cin >> h[h_i];
       
    }
    string w;
    cin >> w;
    rep(i,len(w))
        {
        m=max(m,h[w[i]-'a']);
    }
   // cout<<m;
    cout<<len(w)*m;
       
 return 0;
}