#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <cctype>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <functional>
#include <climits>

#define debug(x) cout << '>' << #x << ':' << x << endl;
#define rep(i,n) for(int i=0;i<(n);i++)
#define forf(i,a,b) for(int i=(a);i<=(b);i++)
#define forb(i,a,b) for(int i=(a);i>=(b);i--)
#define forfstl(v, c) for( typeof( (c).begin()) v = (c).begin();  v != (c).end(); ++v)
#define sz(a) ((int)(a.size()))

#define sd(n) scanf("%d",&n)
#define sc(n) scanf("%c",&n)
#define slld(n) scanf("%lld",&n)
#define sllu(n) scanf("%llu",&n)
#define slf(n) scanf("%lf",&n)
#define ss(n) scanf("%s",n)

#define pd(n) printf("%d",n)
#define pc(n) printf("%c",n)
#define plld(n) printf("%lld",n)
#define pllu(n) printf("%llu",n)
#define plf(n) printf("%lf",n)
#define ps(n) printf("%s",n)
#define pnl printf("\n")

using namespace std;

typedef vector<int> vi;
typedef pair<int,int> pii;
typedef long long int lld;
typedef unsigned long long int llu;

int main()
{
	int ar[28],i,area;
	string st;
   
	for(i=0;i<'z'-'a'+1;i++)
		sd(ar[i]);
	cin>>st;
	area=0;
	for(i=0;i<st.length();i++)
		area = max(area,ar[st[i]-'a']);
	cout<<area*st.length();
	return 0;
}