#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
int cost[26];
char buf[107];
int main()
{
#ifdef LOCAL
	freopen("input.txt", "r", stdin);
#endif
    for (int i = 0; i < 26; i++)
    {
        scanf("%d", &cost[i]);
    }
    scanf("\n");
    scanf("%s", buf);
    int n = strlen(buf);
    int mx = 0;
    for (int i = 0; i < n; i++)
    {
        mx = max(mx, cost[buf[i] - 'a']);
    }
    printf("%d\n", mx * n);
    return 0;
}