/*
 * A.cpp
 *
 *  Created on: Aug 23, 2016
 *      Author: Hazem
 *	Feedback:
 *		-
 *		-
 *		-
 */


#include <iostream>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <vector>
#include <utility>
#include <iomanip>
#include <sstream>
#include <bitset>
#include <cstdlib>
#include <iterator>
#include <algorithm>
/// C Header Files
#include <cstdio>
#include <cctype>
#include <cmath>
#include <math.h>
#include <ctime>
#include <cstring>

using namespace std;

typedef pair<int, int> pii;
typedef pair<int, pii> piii;

#define SET(a)                memset( a, -1,    sizeof a )
#define CLR(a)                memset( a,  0,    sizeof a )
#define MEM(a,val)            memset( a,  val,  sizeof(a) )
#define pb                    push_back
#define all(x)                (x).begin(), (x).end()
#define sz(a)                 int((a).size())
#define ff                    first
#define ss                    second
#define mp                    make_pair
#define nl                    "\n"

int ar[255];
int main()
{
	for(int i =  0 ; i < 26; i++)
		cin>>ar[i];
	string s;
	cin>>s;
	int len = s.size();
	int maxh = 0;
	for(int i = 0 ; i < len; i++)
		maxh = max(maxh, ar[s[i]-'a']);
	cout<<maxh*len<<endl;
}