#include <bits/stdc++.h>

#define PI                    3.14159265359
#define ff                    first
#define ss                    second
#define endl                  "\n"
#define pb                    push_back
#define MOD                   1000000007
#define INF                   INT_MAX
#define fre(x,y)              for(int i=x;i<y;i++)
#define fff(n)                fre(0,n)
#define tt(t)                 while(t--)
#define vi                    vector<int>
#define sz(a)                 int((a).size())
#define space                 " "
#define all(x)                (x).begin(), (x).end()
#define FILEIO                freopen("input.in", "r", stdin);freopen("output.out", "w", stdout);
#define ll                    long long int

using namespace std;
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    
    vi v(26);
    fff(26)cin>>v[i];
    string str;
    cin>>str;
    int max1 = 0;
    fff(str.length())max1 = max(v[str[i]-'a'],max1);
    cout<<str.length()*max1<<endl;
    return 0;
}