#include<bits/stdc++.h>
#define ll long long
#define ld long double
#define fi first
#define se second
ll mpow(ll a, ll n,ll mod)
{ll ret=1;ll b=a;while(n) {if(n&1)
    ret=(ret*b)%mod;b=(b*b)%mod;n>>=1;}
return (ll)ret;
}
using namespace std;
#define sd(x) scanf("%d",&x)
#define pd(x) printf("%d",x)
#define sl(x) scanf("%lld",&x)
#define pl(x) printf("%lld",x)
#define mem(x,a) memset(x,a,sizeof(x))
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define all(v) v.begin(),v.end()
#define N (int)(1e5+25)
int c[26];
void solve(){
    for(int i=0;i<26;i++){
        cin>>c[i];
    }
    int mx=0;
    string s;
    cin>>s;
    for(int i=0;i<s.size();i++){
        mx=max(mx,c[s[i]-'a']);
    }
    int sz=s.size();
    cout<<mx*sz;
}
int main(){
   //freopen("input.txt","r",stdin);
   //freopen("out.txt","w",stdout);
    int t=1;
   // sd(t);
   for(int i=1;i<=t;i++){
       //printf("Case #%d:\n",i);
       solve();
   }
   return 0;
}