#include <bits/stdc++.h>

using namespace std;

#define vec vector
#define ALL(x) (x).begin(), (x).end()
#define mp make_pair

typedef pair< int, int > pii;
typedef long long ll;

int const inf = 1000 * 1000 * 1000;
ll const inf64 = 1ll * inf * inf;

bool solve() {

    vec< int > h(26);

    for(int i = 0;i < 26;i++)
        cin >> h[i];

    string s;
    cin >> s;

    int mx = 0;

    for(char c : s) mx = max(mx, h[c - 'a']);

    cout << mx * (int)s.size() << '\n';

    return true;
}

int main() {

    //while(solve());
    solve();

    return 0;
}