#include<bits/stdc++.h>

using namespace std;

#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define all(x) x.begin(),x.end()
#define sz(x) ((int)x.size())
#define eps 1e-9

const int MOD = 1e9+7;

typedef long long ll;
typedef pair<int,int> pii;

ll POWER[65];
ll power(ll a, ll b) {ll ret=1;while(b) {if(b&1) ret*=a;a*=a;if(ret>=MOD) ret%=MOD;if(a>=MOD) a%=MOD;b>>=1;}return ret;}
ll inv(ll x) {return power(x,MOD-2);}

void precompute() {
	POWER[0]=1;
	for(int i=1;i<63;i++) POWER[i]=POWER[i-1]<<1LL;
}
int ar[27];
int main() {
//	freopen("TASK.in","r",stdin);freopen("TASK.out","w",stdout);
	precompute();
	for(int i=1;i<=26;i++) cin>>ar[i];
	string s;
	cin>>s;
	int maxi=-1;
	for(int i=0;i<sz(s);i++) maxi=max(maxi,ar[s[i]-'a'+1]);
	cout<<maxi*sz(s)<<endl;
	return 0;
}