#include <bits/stdc++.h>
using namespace std;

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

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define rep(i,n) rep2(i,0,n)
#define rep2(i,m,n) for(int i=m;i<(n);i++)
#define ALL(c) (c).begin(),(c).end()

int h[30];
string s;

int main() {
    rep(i, 26) cin >> h[i];
    cin >> s;

    int m = 0;
    rep(i, s.size()) {
	m = max(m, h[s[i]-'a']);
    }
    m *= s.size();
    cout << m << endl;
    
    return 0;
}