#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;

typedef unsigned int uint;
typedef unsigned long long uint64;
typedef long long sint64;

uint h[26];
char s[20];
int main(int argc, char* argv[])
{
    for (uint i = 0; i < 26; ++i)
        cin >> h[i];

    cin >> s;

    uint mh = 0;
    uint l = 0;

    for (; s[l]; ++l) {
        if (h[s[l] - 'a'] > mh)
            mh = h[s[l] - 'a'];
    }

    cout << l * mh << endl;
    return 0;
}