#include<bits/stdc++.h>
#define ll long long int
#define ull unsigned long long int
#define vi vector<int>
#define vii vector<vi>
#define vll vector<ll>
#define mii map<int,int>
#define pii pair<int,int>
#define si set<int>
#define ss set<string>
#define mymod 1000000007
#define mxx 1000
#define myfor(i,n) for(int i=0;i<n;i++)
using namespace std;
int main()
{
    //clock_t tstart = clock();
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int height[26];
	for(int i=0;i<26;i++)
		cin>>height[i];
	string str;
	cin>>str;
	int ans = 0;
	int n = str.length();
	for(int i=0;i<n;i++)
	{
		ans = max(ans,height[str[i]-'a']);
	}
	cout<<ans*n;
	//cout<<"\n\nTotal Time Taken : "<<(double)(-tstart + clock())/CLOCKS_PER_SEC<<"sec\n\n";
	return 0;
}