#include <functional>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <numeric>
#include <iomanip>
#include <cstring>
#include <cassert>
#include <memory>
#include <chrono>
#include <cstdio>
#include <bitset>
#include <vector>
#include <math.h>
#include <queue>
#include <stack>
#include <ctime>
#include <set>
#include <unordered_map>

using namespace std;

#define rep(i,a,n) for (int i=(a);i<(n);i++)
#define per(i,n,a) for (int i=(n)-1;i>=(a);i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;

template <typename T>
T nextInt() {
    T x = 0, p = 1;
    char ch;
    do { ch = getchar(); } while(ch <= ' ');
    if (ch == '-') {
        p = -1;
        ch = getchar();
    }
    while(ch >= '0' && ch <= '9') {
        x = x * 10 + (ch - '0');
        ch = getchar();
    }
    return x * p;
}

const int maxn=(int)3e5+10;
const int inf=(int)1e9+5;
const int mod=(int)1e9+7;
const ll llinf=(ll)1e18+5;
const ld pi=acos(-1.0);

int main(){

   // freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);

    vector<int> c(26);
    rep(i,0,26)cin>>c[i];
    int ret=0;
    string s;
    cin>>s;
    rep(i,0,s.length())ret=max(ret,c[s[i]-'a']);
    cout<<ret*s.length()<<endl;
    return 0;
}