#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ri(x)           scanf("%d",&x)
#define rii(x,y)        scanf("%d%d",&x,&y)
#define riii(x,y,z)     scanf("%d%d%d",&x,&y,&z)
#define riiii(x,y,z,w)  scanf("%d%d%d%d",&x,&y,&z,&w)
#define rl(x)           scanf("%lld",&x)
#define rll(x,y)        scanf("%lld%lld",&x,&y)
#define rlll(x,y,z)     scanf("%lld%lld%lld",&x,&y,&z)
#define rllll(x,y,z,w)  scanf("%lld%lld%lld%lld",&x,&y,&z,&w)
#define rs(str)         scanf("%s",str)
#define pf              printf
#define vi              vector<int>
#define vvi             vector< vi >
#define pii             pair<int,int>
#define vpii            vector< pii >
#define pb              push_back
#define mp              make_pair
#define all(v)          v.begin(),v.end()
#define ms0(X)          memset((X), 0, sizeof((X)))
#define ms1(X)          memset((X), -1, sizeof((X))) 
#define endl            "\n"
#define trace1(X)       cerr << "[debug]: " << X << "\n"
#define trace2(X,Y)     cerr << "[debug]: " << X << " | " << Y << "\n"
#define trace3(X,Y,Z)   cerr << "[debug]: " << X << " | " << Y << " | " << Z << "\n"
#define trace4(X,Y,Z,W) cerr << "[debug]: " << X << " | " << Y << " | " << Z  << " | " << W << "\n"
#define traceA(A,L,R)   cerr << "[debug Array]: "; for (int IIN=L;IIN<=R;++IIN)	cerr << A[IIN] << " ";   cerr << "\n";		// IIN, I'm from IIN :P
#define traceRA(A,R,L)  cerr << "[debug Array]: "; for (int IIN=R;IIN>=L;--IIN)	cerr << A[IIN] << " ";   cerr << "\n";
#define traceDS(c) 		cerr << "[debug Array]: "; for(typeof((c).begin()) i = (c).begin(); i != (c).end();i++) cerr << *i << " ";   cerr << "\n";
#define TC()            int __tc; ri(__tc); while(__tc--)
#define tr(c,i) for(typeof((c).begin()) i = (c).begin(); i != (c).end();i++)
#define lb lower_bound
#define ub upper_bound
#define bs binary_search
#define fi first
#define se second
#if defined(_WIN64)
#define IN freopen("input.txt","r",stdin);
#define OUT freopen("o1","w",stdout);
#else
#define IN {}
#define OUT {}
#endif
const int inf=0x7fffffff;
const int mod=1000000000+7;

inline ll fmod(ll a)
{
	if(a<mod)
		return a;
	else
		return a%mod;
}

int* intarray(int n)
{
	int *array = new int[n];
	
	for(int i=0;i<n;i++)
		ri(array[i]);
	
	return array;
}


ll* llarray(int n)
{
	ll *array = new ll[n];
	
	for(int i=0;i<n;i++)
		rl(array[i]);
	
	return array;
}


int main()
{
	IN
	int *a = intarray(26);
	
	char s[100010];
	rs(s);
	
	int n = strlen(s);
	int mx = 0;
	
	for(int i=0;i<n;i++)
	{
		if(a[s[i]-'a'] > mx)
			mx = a[s[i]-'a'] ;
		
	}
	
	pf("%lld\n",mx*1LL*n);
	return 0;
}