#include <bits/stdc++.h>

using namespace std;

#define forn(i, n) for (int i = 0; i < n; i++)
#define sz(a) (int)a.size()
#define re return
#define fi first
#define se second
#define mp(a, b) make_pair(a, b)

typedef long long ll;
typedef vector<int> vi;
typedef long double ld;
typedef vector<ll> vll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

int a[26];
string s;
int main() {
	iostream::sync_with_stdio(0), cin.tie(0);
	//freopen("a.in", "r", stdin);
	//freopen(".out", "w", stdout);
	forn (i, 26) cin >> a[i];
	cin >> s;
	int ma = 0;
	forn (i, sz(s))
		ma = max(ma, a[s[i] - 'a']);
	cout << ma * sz(s);
	re 0;
}