#include<bits/stdc++.h>
 
#define gc getchar
#define ii(x) scanf(" %d", &x)
#define ill(x) scanf(" %lld", &x)
#define ll long long
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define fill(a,b) memset(a, b, sizeof(a))
#define rep(i,a,b) for(i=a;i<b;i++)
#define per(i,a,b) for(i=a;i>=b;i--)
#define pii pair<int, int>
 
using namespace std;
 
void in(int &x){
    register int c=gc();
    x=0;
    for(;(c<48||c>57);c=gc());
    for(;c>47&&c<58;c=gc()){x=(x<<1)+(x<<3)+c-48;}
}

int main()
{
	int a[30],i,n;
	string s;
	rep(i, 0, 26) in(a[i]);
	cin >> s;
	int shit = 0;
	rep(i, 0, s.length()){
		shit = max(shit, a[s[i]-'a']);
	}
	cout << shit * s.length() << endl;

	return 0;
}