#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <string>
#include <iomanip>
#include <set>
#include <utility>
#include <vector>
#include <fstream>
#include <map>
#include <deque>
#include <queue>
#include <cstring>
#include <cstdio>
#include <list>
#include <bitset>

using namespace std;

const long long INF = 1e18;
const int MAXN = 1e5 + 1, MODM = 1e9 + 7;

#define ABS(x) ((x) < 0 ? -(x) : (x))
#define ll long long
#define ld long double
#define all(a) a.begin(), a.end()
#define pii pair<ld, ld>
#define forn(i, n) for(int i = 0; i < n; i++)
#ifdef DEBUG 
	#define NAME "1"
#else
	#define NAME "cakes"
#endif
#define FREOPEN freopen(NAME".in", "r", stdin); freopen(NAME".out", "w", stdout)
#define PI 3.1415926535897932384626433832795
#define y second
#define x first

int main() {
	ios_base::sync_with_stdio(0);
	vector<int> a(26, 0);
    forn(i, 26)
            cin >> a[i];
    string s;
    cin >> s;
    int ans = -1;
    forn(i, s.size()) {
        ans = max(ans, a[s[i] - 'a']);
    }
    cout << ans * s.size();
	//#ifdef DEBUG
  	//	cout << "\n\nTIME ELAPSED: " << ((float)clock()) / CLOCKS_PER_SEC << "\n";
	//#endif
	return 0;
}