#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <iomanip>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cassert>
#include <cstdlib>
#include <ctime>

using namespace std;

#define rep(i,n) for(int i=0;i<n;i++)
#define ll  long long int
#define f first
#define s second
#define pi pair<ll, ll>
#define pii pair<pi,ll>
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define pb push_back
#define rep(i,n) for(int i=0;i<n;i++)
#define fr freopen("source.txt","r",stdin),freopen("output.txt","w",stdout)

int main(){
//	fr;
	ll f[26];
	rep(i,26){
		cin >> f[i];
	}
	string s;
	cin >> s;
	ll m=0;
	rep(i,s.size()){
		m=max(m,f[s[i]-'a']);
	}
	m*=(ll)s.size();
	cout<<m;
}