#include <bits/stdc++.h>
using namespace std;

//0 1->codeforces
#define LL "%lld"
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define PN printf("\n")
#define MODV 1000000007

typedef long long ll;
typedef double dbl;
typedef vector<int> vi;
typedef pair<int, int> pi;
void addmod(int &a, ll b){a=(a+b); if(a>=MODV)a-=MODV;}
void mulmod(int &a, ll b){a=(a*b)%MODV;}
int gi(){int a;scanf("%d",&a);return a;}
ll gll(){ll a;scanf(LL,&a);return a;}

int main() {
  vi a(26);
  for(auto i=0;i<26;i++){ a[i]=gi(); }
  char *s;
  s = new char[100];
  scanf("%s", s);
  int n=strlen(s), ml=0;
  for(int i=0;i<n;i++){
    ml=max(ml,a[s[i]-'a']);
  }
  cout<<ml*n<<endl;
  
  return 0;
}