#include <bits/stdc++.h>
#define MAX 400005
#define inf 10000000000000000
#define ll long long
#define MOD 1000000007
#define s(x) scanf("%d", &x);

using namespace std;

int a[27];
int main()
{
    for(int i = 0 ; i < 26; i++) {
        cin >> a[i];
    }
    string s;
    cin >> s;
    int mx = 0;
    for(int i = 0; i < s.size(); i++) {
        if( a[s[i] - 'a'] > mx) {
            mx = a[s[i] - 'a'];
        }
    }
    cout << mx * s.size() << endl;
}