#include <bits/stdc++.h>
#define ll long long
#define fo(i,n) for(i=0;i<n;++i)
#define forr(i,n) for(i=n-1;i>=0;--i)
using namespace std;

ll gcd(ll a,ll b){while(a&&b)a>b?a%=b:b%=a;return a+b;}
ll lcm(ll a,ll b){return a*b/gcd(a,b);}

int main(){
	ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	cerr<<"Start"<<endl;
	int i;
	int a[26];
	fo(i,26)
		cin>>a[i];
	string s;
	int max = 0;
	cin>>s;
	fo(i,s.length()){
		a[s[i]-'a']>max?max=a[s[i]-'a']:max=max;		
	}
	cout<<s.length()*max<<endl;
	return 0;
}