#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;

string s;
long long b,h;
long long i=0;
vector <int> v;
priority_queue <int> pq;
long long x;
int main(){
    for(i=0;i<26;i++)
        {
        cin>>x;
        v.push_back(x);
        
    }
    cin>>s;
    b=s.length();
    for(i=0;i<s.length();i++)
        {
        pq.push(v[s[i]-97]);
    }
    h=pq.top();
    cout<<h*b;
    return 0;
}