#include<bits/stdc++.h>
#define mod 1000000007
#define len(a) strlen(a)
#define ll long long
#define nl printf("\n")
#define F first
#define S second

#define db printf("debug")
#define yes printf("YES\n")
#define no printf("NO\n")
#define pb(a) push_back(a)
#define po(a) pop_back()
#define mp(a,b) make_pair(a,b)
#define set(a,v) memset(a,v,sizeof(a))
#define sz(v) v.size()
#define gc getchar//_unlocked

#define pcase(i) printf("Case %d:\n",i)
using namespace std;

int a[27];
int main()
{
    int i,x,mx=-1;
    string s;

    for(i=0;i<26;i++)
    {
        cin>>a[i];
    }
    cin>>s;
    int l= s.length();
    for(i=0;i<l;i++)
    {
        x= s[i]-'a';
        mx= max(mx, a[x]);
    }
    cout<<l*mx;
}