#include<bits/stdc++.h> //_Shaffi
using namespace std;
#define sc scanint
#define sl scanlong
#define gc getchar
#define f first
#define s second
#define DO int t; scanf("%d",&t); while(t--)
typedef long long ull;
typedef vector<int> vi;
void scanint(int &x);
void scanlong(ull &x);
void scanint(int &x)
{
        int flag=0;
        register int c = gc();
        if(c == '-') flag=1;
	x = 0;
	for(;(c<48 || c>57);c = gc());
	for(;c>47 && c<58;c = gc()) {x = (x<<1) + (x<<3) + c - 48;}
        if(flag == 1)x=-x;
}
void scanlong(ull &x)
{
        int flag=0;
        register int c = gc();
        if(c == '-') flag=1;
	x = 0;
	for(;(c<48 || c>57);c = gc());
	for(;c>47 && c<58;c = gc()) {x = (x<<1) + (x<<3) + c - 48;}
        if(flag == 1)x=-x;
}
int main()
{
    vi arr; int i,max1=0;
    for(i=0;i<26;i++)
    {
        int a; sc(a); arr.push_back(a);
    }
    string s; getline(cin>>ws,s);
    for(i=0;i<s.length();i++)
    {
        int temp=s[i]-'a';
        int b=arr[temp];
        max1=max(b,max1);
    }
    cout<<max1*s.length();
}