#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MOD 1000000007
#define INF 1e18
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define pi pair<ll,ll>
ll a[26];
int main()
{
	for(int i=0;i<26;i++)
	{
		cin>>a[i];
	}
	string s;
	cin>>s;
	ll n=s.length();
	ll m=0;
	for(int i=0;i<n;i++)
	{
		m=max(m,a[s[i]-'a']);
	}
	cout<<m*n<<endl;
	return 0;
}