#include <bits/stdc++.h>

using namespace std;
using LINT = long long int;
using PII = pair<int,int>;

#define PB push_back
#define FI first
#define SE second
#define REP(i,n) for(int i=0;i<(n);++i)
#define FOR(i, a, b) for(int i=(a);i<(b);++i)

int arr[27];

int main() {
    REP(i,26)cin>>arr[i];
    string s;
    cin >> s;
    int lemax = -1;
    for(char c:s)
        lemax = max(lemax, arr[c-'a']);
    cout<<lemax*s.size()<<endl;
    
    return 0;
}