#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define si(x) scanf("%d",&x)
#define sl(x) scanf("%lld",&x)
#define sd(x) scanf("%lf",&x)
#define sc(x) scanf("%c",&x)
#define ss(x) scanf("%s",x)
#define vl vector<ll>
#define vi vector<int>
#define pb push_back
#define mod 1000000007

	
#define MAXN 200110
#define SQRT 330
#define ls (node<<1)
#define rs ((node<<1)+1)
#define ii pair<int,int>
#define F first
#define S second

ll modpow(ll base, ll exponent,ll modulus){
	if(base==0&&exponent==0)return 0;
	ll result = 1;
	while (exponent > 0){
		if (exponent % 2 == 1)
		    result = (result * base) % modulus;
		exponent = exponent >> 1;
		base = (base * base) % modulus;
	}
	return result;
}


int H[MAXN];

string str;

inline void ReadInput(void){
	for(int i = 0; i < 26; i++) cin >> H[i];
	cin >> str;
}

inline void solve(void){
	int h = 0, w = (int)str.length();
	for(int i = 0; i < w; i++){
		h = max(h, H[str[i] - 'a']);
	}
	cout << h * w << endl;
}

inline void Refresh(void){
	
}

int main()
{	
	//ios_base::sync_with_stdio(false);
	ReadInput();
	solve();
    return 0;
}