#include<bits/stdc++.h>
#define ll long long
using namespace std;
int main()
{
    map<char,ll>m;
    ll temp=97;
    for (ll i=0;i<26;i++)
    {
        char c=(char)temp;
        ll num;
        cin>>num;
        m[c]=num;
        temp++;
    }
    string s;
    cin>>s;
    ll maxi=0;
    for ( ll i=0;i<s.size();i++)
    {
       // cout<<s[i]<<endl;
        if (maxi<=m[s[i]])
            maxi=m[s[i]];
    }
    cout<<maxi*s.length()<<endl;
}