#include<bits/stdc++.h>
#define Max 100005
#define inf 10000000000 + 7
#define ll long long
#define open() freopen("input.txt","r",stdin)
#define show() freopen("output.txt","w",stdout)
#define pb push_back
using namespace std;
int dp[Max],ara[Max],A[Max],C[Max],cnt[Max];
int main(){

    //open();
    //show();
    int ch[50];
    int t,cas=1,n,k;
    //scanf("%d",&t);
      for(int i=1;i<=26;i++){
        cin>>ch[i];
      }
      string str;
      cin>>str;
      int len=str.size();
      int mx=0;
      for(int i=0;i<len;i++){
        mx=max(mx,ch[str[i]-'a'+1]);
      }
      cout<<mx*len<<endl;
       //printf("%d\n",dp[k]);
    return 0;
}