#include <iostream>
#include <cstdio>
#include <cassert>
#include <cstring>
#include <vector>
#include <valarray>
#include <array>
#include <queue>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <algorithm>
#include <cmath>
#include <complex>
#include <random>

using namespace std;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
template<class T = ll> constexpr T TEN(int n) {return (n==0)?1:10*TEN<T>(n-1);}

int main() {
    int a[26];
    for (int i = 0; i < 26; i++) {
        cin >> a[i];
    }
    string s;
    cin >> s;
    int h = -1;
    for (char c: s) {
        h = max(h, a[c-'a']);
    }
    cout << int(s.size()) * h << endl;
    return 0;
}