#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i = (a); i <= (b); ++i)
#define FORD(i,a,b) for(int i = (a); i >= (b); --i)
#define RI(i,n) FOR(i,1,(n))
#define REP(i,n) FOR(i,0,(n)-1)
#define mini(a,b) a=min(a,b)
#define maxi(a,b) a=max(a,b)
#define mp make_pair
#define pb push_back
#define st first
#define nd second
#define sz(w) (int) w.size()
typedef vector<int> vi;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<pii, int> para;
const int inf = 1e9 + 7;
const int maxN = 1e6 + 5;

string s;
int height[100];

int main() {
	REP(i, 26) cin>>height[i];
	cin>>s;
	int maxim = 0;
	REP(i, sz(s)) {
		maxi(maxim, height[s[i] - 'a']);
	}
	cout<<maxim * sz(s);
	return 0;
}