#include <iostream>
#include <map>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;
map<char,int> mp;
int main(int argc, char** argv) {
	for(int i = 0 ; i < 26; i++){
		char x = 'a'+i;
		int t;
		cin>>t;
		mp[x]=t;
	}
	string s;
	cin>>s;
	int best =0;
	for(int i = 0; i < s.size(); i ++){
		if(mp[s[i]]>best) best =mp[s[i]];
	}
	cout<<best*s.size();
	return 0;
}