#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#define fread(ch) freopen(ch,"r",stdin)
#define fwrite(ch) freopen(ch,"w",stdout)
#define Pr pair<int,int>
#define VI vector<int>
#define LL long long

using namespace std;
const int INF = 0x3f3f3f3f;
const int mod = 1e9+7;
const double eps = 1e-8;

int height[26];

int main()
{
    char str[33];

    for(int i = 0; i < 26; ++i) scanf("%d",&height[i]);

    scanf("%s",str);

    int h = 0;
    for(int i = 0; str[i]; ++i)
    {
        h = max(h,height[str[i]-97]);
    }

    printf("%d\n",h*strlen(str));

    return 0;
}