#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <bits/stdc++.h>
#include <sstream>
using namespace std;

#define endl '\n'
typedef long long LL;
typedef pair <int, int> pii;
typedef pair <int, pii> piii;
typedef map <int, int> mii;
typedef multimap <int, int> mmii;
typedef vector <int> vi;
typedef vector < pii > vpii;
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define FAST1 ios_base::sync_with_stdio(0)
#define FAST2 cin.tie(0);cout.tie(0); cerr.tie(0)
#define FOR(a,b,c) for(a=b;a<c;a++)
#define mp(a,b)  make_pair(a,b)
#define pb(a,b) a.push_back(b)
#define F first
#define S second
const long double EPS = 1e-9;
const LL MOD = 1000000007;
const LL MAXN = 100010;

int main(void){
	vi a;
	int i,j,k,max;
	string s;
	FOR(i,0,26){
		cin>>j;
		pb(a,j);
	}
	cin>>s;
	k = s.length();
	max = a[s[0]-'a'];
	for(auto i:s)
		if(a[i-'a']>max)
			max = a[i-'a'];
	cout<<max*k<<endl;
	return 0;
}