#include<bits/stdc++.h>
using namespace std;
#define fastScan ios_base::sync_with_stdio(0); cin.tie(NULL);
#define fill(a,x) memset(a,x,sizeof(a))
#define ll long long int
#define MAX 200
#define M 1000000007
#define pii pair<int,int>
#define pll pair<ll,ll>
#define mb make_pair
#define pb push_back
#define rep(i,n) for(int i=0;i<n;i++)
#define repp(i,a,b) for(int i=a;i<=b;i++)
#define reff(i,a,b) for(int i=a;i>=b;i--)
#define F first
#define S second
#define DBG1(a)         std::cerr<<#a<<"="<<(a)<<"\n"
#define DBG2(a,b)       std::cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<"\n"
#define DBG3(a,b,c)     std::cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<"\n"
#define DBG4(a,b,c,d)   std::cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<", "<<#d<<"="<<(d)<<"\n"
#define DBG5(a,b,c,d,e) std::cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<", "<<#d<<"="<<(d)<<", "<<#e<<"="<<(e)<<"\n"
const int INF = 2034567891;
const ll INF64 = 1234567890123456789ll;
int main()
{	
    fastScan;
    ll a[26];
    rep(i,26)
    cin>>a[i];
    string s;
    cin>>s;
    ll h=0;
    rep(i,s.size())
    {
    	if(a[s[i]-'a']>h)
    	h=a[s[i]-'a'];
	}
	cout<<h*s.size();
}