#include<bits/stdc++.h>
#define f(i,a,n) for(int i=a;i<n;i++)
#define S second
#define F first
#define Sc(n) scanf("%lld",&n)
#define scc(a,b,c) scanf("%lld %lld %lld",&a,&b,&c)
#define sp(a) scanf("%lld %lld",&a.first,&a.second)
#define pb push_back
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define all(a) a.begin(),a.end()
#define sc(n) scanf("%d",&n)
#define It iterator
#define SET(a,b) memset(a,b,sizeof(a))
#define DRT()  int t; cin>>t; while(t--)
// inbuilt functions
// __gcd,  __builtin_ffs,     (returns least significant 1-bit, __builtin_ffsll(1)=1)
// __builtin_clz,             (returns number of leading zeroes in 
// __builtin_popcount,
using namespace std;
typedef long long LL;
typedef pair<int,int> PII;
typedef vector<int> vi;
#define tr(container, it) for(__typeof(container.begin()) it = container.begin(); it != container.end(); it++)
#define trv(s,it) for(auto it:s)
int h[30];
int main()
{	string s;
	s.clear();
	f(i,0,26)
		sc(h[i]);
	cin>>s;
	int m=0;
	f(i,0,s.size())
		m=max(m,h[s[i]-'a']);
	cout<<m*s.size()<<endl;
}