#include<bits/stdc++.h>
#define ll          long long int
#define pb          emplace_back
#define mp          make_pair
#define pii         pair<int,int>
#define vi          vector<int>
#define Max(a,b)    ((a)>(b)?(a):(b))
#define Min(a,b)    ((a)<(b)?(a):(b))
#define rep(i,a,b)  for (__typeof((b)) i=(a);i<(b);i+=1)
#define all(a)      (a).begin(),(a).end()
#define F           first
#define S           second
#define sz(x)       (int)x.size()
#define hell        1000000007
#define endl        '\n'
#define debug(a)    cerr<<#a<<": ";for(auto i:a)cerr<<i<<" ";cerr<<'\n';
using namespace std;

void solve(){
    vi x(26);
    rep(i,0,26)cin>>x[i];
    string s;
    cin>>s;
    int h=0;
    for(auto i:s){
        h=max(h,x[i-'a']);
    }
    cout<<h*sz(s);
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int t=1;
//	cin>>t;
	while(t--){
		solve();
	}
	return 0;
}