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

// Numeric Constants
#define N 1000000007
#define maxs 200005
#define mins 1005
#define eps 1e-14
#define imax 2000000200
#define llmax 1000000002000000000ll
#define pi 3.141592653589793

// Others
#define ll long long
#define pb push_back
#define gc getchar_unlocked
#define iosbase ios_base::sync_with_stdio(false)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define ppi pair<pair<int,int>,int>
#define ppl pair<pll,ll>
#define vi vector<int>
#define sc scanf
#define pr printf
#define lld I64d
#define F first
#define S second
#define siter set<int>::iterator
#define p_pq priority_queue
#define ub upper_bound
#define lb lower_bound

ll arr[maxs];
string str;
int main()
{
	ll n,m,i;
	for(i=0;i<26;i++){
		cin>>arr[i];
	}
	cin>>str;
	ll h=0;
	for(i=0;i<str.size();i++){
		h=max(h,arr[str[i]-'a']);
	}
	ll ans=h*(ll)str.size();
	cout<<ans<<"\n";
	return 0;
}