#include <iostream>
#include <cstdio>
#include<unordered_map>
#include<unordered_set>
#include <algorithm>
#include <cstring>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cmath>
#include<cassert>
#include <set>
#include<sstream>
#include<iomanip>
#include<numeric>
#include <climits>
#include<string>

#define PI acos(-1)
#define mp make_pair
#define pb push_back
#define eps 1e-9
#define fi first
#define se second
#define endl '\n'
#define io  ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define file freopen ("input.txt", "r", stdin),freopen ("output.txt", "w", stdout);
#define filein freopen ("in.txt", "r", stdin);
#define all(v) ((v).begin()), ((v).end())
//#define mid ((st + en) >> 1)

using namespace std;

typedef long double ld;
typedef unsigned long long ull;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;
typedef vector<vector<long long> > matrix;
typedef pair<pii, int> piii;

string a;
int h[26];

int main(){ 
	for(int i = 0; i < 26; i++)
		cin >> h[i];
	cin >> a;
	int cur = 0;
	int n = (int)a.size();
	for(int i = 0; i < n; i++)
		cur = max(cur, h[a[i] - 'a']);
	cout << n * cur << endl;
	return 0;
}