#include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define MOD 1000000007
typedef long long Int;
typedef pair<Int,Int> pii;
typedef vector<Int> vi;
typedef vector<pii> vii;
Int h[200];
int main()
{
    for (Int i='a';i<='z';++i)
        cin>>h[i];
    string S;
    cin>>S;
    Int maxm=0;
    for (Int i=0;i<S.size();++i)
        maxm=max(maxm,h[S[i]]);
    cout<<maxm*S.size();
    return 0;
}