#include <vector>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include<iomanip>
using namespace std;

typedef long long ll;
typedef vector <int> vi;
typedef pair< int ,int > pii;
#define pb push_back
#define sz size()
#define ln length()
#define fore(i,a,b) for(int i=a;i<b;i++)
#define fores(i,a,b) for(int i=a;i<=b;i++)
#define ford(i,a,b) for(int i=a;i>=b;i--)
#define all(a) a.begin(),a.end()
#define mp make_pair
#define ff first
#define ss second
#define sc(a) scanf("%d",&a)
#define md 1000000007

int main() {
    vi a(26,0);
    fore(i,0,26) {
        cin>>a[i];
    }
    string s;
    cin>>s;
    int ma = 0;
    fore(i,0,s.ln) {
        ma = max(ma, a[s[i]-'a']);
    }
    ma*=s.ln;
    cout<<ma;
    return 0;
}