/* Success consists of going from failure to failure without loss of enthusiasm. - Winston Churchill
 */
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <sstream>
#include <set>
#include <iomanip>
#include <list>
#include <stack>
#include <queue>
#include <bitset>
#include <numeric>
#include <functional>
#include <unordered_map>

#include <cstdio>
#include <cmath>
#include <climits>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <cassert>
using namespace std;

#define tr(x) cout << x << endl;
#define tr2(x, y) cout << x << " " << y << endl;
#define tr3(x, y, z) cout << x << " " << y << " " << z << endl;
#define tr4(w, x, y, z) cout << w << " " << x << " " << y << " " << z << endl;
#define tr6(a, b, w, x, y, z) cout << a << " " << b << " " << w << " " << x << " " << y << " " << z << endl;

#define ll long long
#define fastIO  ios::sync_with_stdio(false); cin.tie(0);
inline int in() { int x; scanf("%d", &x); return x; }
inline long long inL() { long long x; scanf("%lld", &x); return x; }

string toString(long long n) { stringstream ss; ss << n; return ss.str(); }
long long toNumber(string s){ stringstream ss; long long n; ss << s; ss >> n; return n; }

const int N = 1e5 + 9;




int main(){
#ifdef __APPLE__
    const clock_t begin_time = clock();
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
#endif

    map <char, int> a;
    for (char c = 'a'; c <= 'z'; c++) {
        int x = in();
        a[c] = x;
    }
    
    string s; cin >> s;
    ll area = s.length();
    ll maxi = -1;
    for (char c : s) {
        maxi = max(a[c]*1LL, maxi);
    }
    
    cout << area * maxi << endl;
    
#ifdef __APPLE__
    cout << endl;
    cout << "Time : ";
    cout << float( clock () - begin_time ) / CLOCKS_PER_SEC << endl;
#endif
    
    return 0;
    
}