//Header
#include<bits/stdc++.h>
using namespace std;
// Global declarations
typedef long long int ll;
typedef vector<int> vi;
typedef vector<char> vc;
typedef pair<int, int> pi;
typedef pair<ll, ll> pll;
typedef vector<pi> vpi;
typedef vector<pll> vpll;
typedef vector<ll> vll;
const int mod = 1e9 + 7;
const int INF = 1 << 29;
const double eps = 1e-14;
// Macros
#define mp make_pair
#define el putchar('\n')
#define sp putchar(' ')
#define Fill(a,val) memset(a,val,sizeof a)
#define all(a) a.begin(),a.end()
#ifndef ONLINE_JUDGE
#define tr(a, it) for (decltype(a.begin()) it = a.begin(); it != a.end(); ++it)
#else
#define tr(a, it) for (typeof(a.begin()) it = a.begin(); it != a.end(); ++it)
#endif
#define in(n) scanf("%d",&n);
#define inl(n) scanf("%lld",&n);
#define out(n) printf("%d",n);
#define outl(n) printf("%lld",n);

int main(){
	int h[26];
	for (int i = 0; i < 26; ++i)
		in(h[i]);
	string a;
	cin >> a;
	int n = a.length();
	int mx = 0;
	for (int i = 0; i < n; ++i){
		mx = max(mx, h[a[i] - 'a']);
	}
	cout << mx*n; el;
	return 0;
}