#include<bits/stdc++.h>
using namespace std;
#define D(x)        cout<<#x " = "<<(x)<<endl
#define un(x)       x.erase(unique(x.begin(),x.end()), x.end())
#define sf(n)       scanf("%d", &n)
#define sff(a,b)    scanf("%d %d", &a, &b)
#define sfff(a,b,c) scanf("%d %d %d", &a, &b, &c)
#define pb          push_back
#define mp          make_pair
#define xx          first
#define yy          second
#define hp          (LL) 999983
#define MAX         100000
#define eps         1e-9
#define pi          acos(-1.00)
typedef long long int LL;
typedef pair<int,int> pii;

char str[MAX];
int h[MAX+5];

int main()
{
    //freopen("in.txt", "r", stdin);
    int i, j, k, mx = 0;

    for(i = 0; i < 26; i++)
        sf(h[i]);

    scanf("%s", str);
    for(i = 0; str[i]; i++)
    {
        mx = max(mx, h[str[i] - 'a']);
    }

    cout << mx * strlen(str) << endl;
    return 0;
}