#include <bits/stdc++.h>
using namespace std;

#define MOD 1000000007
#define pb push_back
#define mp make_pair
#define all(c) (c).begin(),(c).end()
#define sz(a) int((a).size())
#define F first
#define S second

#define rep(i, a, b) for(int i = a; i < b; ++i)

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef pair<int, pii> piii;
typedef vector<pii> vpii;
typedef vector<piii> vpiii;

inline ll powmod(ll x, ll n, ll _mod){ 
  ll res = 1; 
  while (n){
    if (n & 1)res = (res*x) % _mod; 
    x = (x*x) % _mod; 
    n >>= 1;
    }
    return res; 
  }

#define N 100005

int a[27];

int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//freopen("a.txt","r",stdin);  //freopen("o.txt","w",stdout);
int mx=0;
rep(i,0,26){
  cin>>a[i];
}
string s;
cin>>s;

rep(i,0,sz(s)){
  mx=max(mx,a[s[i]-'a']);
}

int ans=(int)s.size()*mx;
cout<<ans<<'\n';
return 0;
}