#include <bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define pii pair<int, int>
#define pll pair<long long, long long>
#define vi  vector<int>
#define pb  push_back
#define mp  make_pair
#define ALL(x) x.begin(),x.end()
#define M(a,x) memset(a,x,sizeof(a))
#define sci(x) scanf("%d",&x);
#define scl(x) scanf("%lld",&x);
#define scs(x) scanf("%s",x);
#define SZ(x) (int)x.size()
#define print(x) printf("%d",x);
#define nl printf("\n")
#define fr first
#define se second
#define printl(x) printf("%lld",x)
#define F(i,a,n) for(int i=a;i<n;i++)
#define INF 100000000000000000LL
#define LL long long

const int N = 1e5+5;
int a[50];
int main() {
  for(int i = 0 ; i < 26 ; i++) {
    cin >> a[i];
  }
  string s;
  cin >> s;
  int ans = 0;
  for(int i = 0 ; i < s.size() ; i++) {
    ans = max(ans,a[s[i]-'a']);
  }
  cout<<ans*s.size()<<endl;
}