#include <iostream>
#define For(x, n) for(int x=0; x<n; x++)
using namespace std;
int main() {
    int h[26];
    For(i, 26)
        scanf("%d", &h[i]);
    string s;
    cin>>s;
    int max = h[s[0] - 'a'];
    For(i, s.length()) {
        if(max < h[s[i] - 'a'])
            max = h[s[i]-'a'];
    }
    cout<<s.length() * max;
    return 0;
}