#include<bits/stdc++.h>
using namespace std;
#define test() int t;scanf("%d",&t);for(int tno=1;tno<=t;tno++)
#define FOR(i, begin, end) for (i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))
#define mp make_pair
#define pb push_back
#define wl(n) while(n--)
#define fi first
#define se second
#define all(c) c.begin(),c.end()
typedef long long ll;
typedef unsigned long long llu;
typedef vector<int> vi; 
typedef pair<int,int> pii;
#define sz(a) int((a).size())
#define ini(a,v) memset(a,v,sizeof(a))
#define sc(n) scanf("%d",&n)
#define sc2(n,m) sc(n), sc(m)
#define scs(s) scanf("%s",s);
#define scl(n) scanf("%lld",&n)
#define scl2(n,m) scanf("%lld%lld",&n,&m)
#define newln printf("\n")
#define space printf(" ")
#define debug() 				printf("here\n")
#define printvec(v)       		{ for(int i=0;i<v.size();i++) printf("%d ",v[i]);printf("\n"); }
#define printarr(a,st,ed)    	{ for(int i=st;i<ed;i++) printf("%d ",a[i]);printf("\n"); }  
#define chk(a) cerr << endl << #a << " : " << a << endl
#define chk2(a,b) cerr << endl << #a << " : " << a << "\t" << #b << " : " << b << endl
#define MOD 1000000007
#define inf ((1<<29)-1)
#define linf ((1LL<<60)-1)
const double eps = 1e-9;
//-----------------------------------------------------------------------------------------------

const int MAX = 200009;

ll a[MAX]={0};

int main()
{
	int i,j,k;
	for(i=0;i<26;i++){
		scl(a[i]);
	}
	char s[MAX];
	scs(s);
	int l = strlen(s);
	ll mx=0;
	for(i=0;i<l;i++){
		mx = max(mx,a[s[i]-'a']);
	}
	printf("%lld\n",l*mx);
	return 0;
}