#include <iostream>
#include <stdio.h>
#include <cstdio>
#include <string>
#include <cmath>
#include <cstring>
#include <ctype.h>
#include <ctime>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>
#include <stack>
#define read()     freopen("C:/Users/MASUDUR RAHMAN/Desktop/input.txt","r",stdin)
#define write()    freopen("C:/Users/MASUDUR RAHMAN/Desktop/output.txt","w",stdout)
#define mem(a, b)  memset(a, b, sizeof(a))
#define sc(n)      scanf("%d",&n)
#define scc(a,b,w) scanf("%d %d %d",&a, &b, &w)
#define all(road)  road.begin(), road.end()
#define uu         first
#define vv         second
#define sp         <<' '
#define nwl        <<endl
#define inf        1000000
#define mx         100005
#define pi         acos(-1)
#define mod        1000000007
#define itn        int
#define lg(n)      63-__builtin_clzll(n)
#define ones(n)    __builtin_popcountll(n)
using namespace std;
typedef pair <int, itn> pii;
typedef long long lli;

int h['z'+5];
int main()
{
   int x;
   for(char i='a'; i<='z'; i++){
      cin>>x; h[i]=x;
   }
   int m=0, n=0;
   string str;
   cin>>str;
   n=str.size();
   for(int i=0; i<n; i++){
      m=max(m, h[str[i]]);
   }
   cout<<n*m<<endl;
   return 0;
}