#include<bits/stdc++.h>   

#define F first    
#define S second
#define mp make_pair
#define pii pair<int,int>         
// mikty prikoldar
#define ll long long  
#define pb push_back
#define sz(a) (int)(a.size())
#define Accepted 0
#define endl '\n'
//everything goes according to the plan
#define y1 		 NOT
#define left   NEEDED
#define right  THINGS  
//countdown BEGAN. 10 , 9 , 8 ...
const int Mod = (int)1e9 + 7;
const int MX = 1073741822;
const ll MXLL = 9223372036854775807;
const int Sz = 1110111;
// ai dyn dyn dyn dirindai ai dyn dyn dirindai
using namespace std;
// skr skr skr v chernih naikah
inline void Read_rap () {	// smoke weed everyday
  ios_base :: sync_with_stdio(0);
	cin.tie(0);      
}
string s;

int h[Sz];                        

int main() 
{
	Read_rap ();
	for (int i = 'a';i <= 'z';i ++)	cin >> h[i];

	cin >> s;    

	int mx = 0;
	for (int i = 0;i < sz(s);i ++)	mx = max (mx, h[s[i]]);


	cout << mx * sz(s);


	return Accepted;
}	









// Coded by Z...