#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<ll,ll> pii;    
typedef vector<ll> vii;

#define X first
#define Y second
#define rep(i,n) for(ll i=0; i<(n); i++)
#define repp(i,a,b) for(ll i=a; i<=(b); i++)
#define repp2(i,b,a) for(ll i=b; i>=(a); i--)
#define fill(a,val) memset(a, (val), sizeof(a))
#define mp make_pair
#define pb push_back
#define all(c) (c).begin(), (c).end()
#define uni(c) c.resize(distance(c.begin(), unique(all(c))))
#define io ios_base::sync_with_stdio(false);cin.tie(NULL);
#define sc(num) scanf("%lld",&num)
//#define ONLINE
#ifdef ONLINE
FILE *fin = freopen("great.in","r",stdin);
FILE *fout = freopen("great.out","w",stdout);
#endif

ll mod= 1e9 + 7, mod1=1e9+9;
double eps = 1e-16;
const ll N=100005;


int main(){
    io;
    
    int a[26];
    rep(i,26)cin>>a[i];
    string s;
    cin>>s;
    int ma=0;
    for(auto x:s){
        ma=max(ma,a[x-'a']);
    }
    
    cout<<ma*(s.size());
    return 0;
}