#include<bits/stdc++.h>
#define f(i,l,r) for(i=l;i<r;i++)
#define fr(i,r,l) for(i=r;i>l;i--)
#define s(n) scanf("%lld",&n)
#define pl(n) printf("%lld\n",n)
#define ss(s) scanf("%s",s);
#define sz size()
#define ll long long int
#define pb push_back
#define mp make_pair
#define vll vector<ll>
#define pll pair<ll,ll>
#define vpll vector< pll > 
#define F first
#define S second
#define mod 1000000007
#define maxa 1000005
#define maxv 100000000000000009
#define pi 3.14159265358979323846
#define all(v) v.begin() , v.end()
using namespace std;
//#include "debug.h"
#define PLD(vale) cout << fixed; cout.precision(20); cout << vale <<"\n" 
ll prod(ll a,ll b){ ll x,d;if(b==0)return 1;
    else{d=prod(a,b/2);x=(d*d)%mod;if(b%2==0)return x;
        else return (x*(a%mod))%mod;}
}
int main(){
    ll i,hei,h[1000],l;
    char s[10005];
    f(i,0,26){
        s(h[i]);
    }
    ss(s);
    l = strlen(s);
    hei = -1;
    f(i,0,l){
        hei = max(hei,h[s[i]-'a']);
    }
    pl(hei*l);
    return 0;
}