#include<bits/stdc++.h>
 
#define LL long long 
#define sn(n) scanf("%d",&n) ;
#define all(n) n.begin() , n.end()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define INF 0x7fffffff
#define fast_io ios::sync_with_stdio(0) ; cin.tie(0) ; 
#define in() freopen("input.txt" , "r" , stdin) ;
#define MOD 1000000007
#define debug() cout << "HI" << endl ;
 
using namespace std ;

int main()
{
    // #ifndef ONLINE_JUDGE
    //     in() ;
    // #endif
    fast_io ;
    int arr[200] ;
    for(int i = 'a'; i <= 'z'; ++i)
    {
        cin >> arr[i] ;
    }
    string s ;
    cin >> s ;
    int ans = 0 ;
    for(int i = 0; i < s.size(); ++i)
    {
        ans = max(ans,arr[s[i]]) ;
    }
    cout << ans*s.size() << endl ;
    
    return 0 ;
}