from fractions import gcd
aaa=gcd(4,10)
#  n=input()
#  n,m=map(int,raw_input().split())
#  l=list(map(int,raw_input().split()))
pr="biggy_bs"
aa=pow(10,10,10)
l=list(map(int,raw_input().split()))
s=raw_input()
li=[0]*26
for i in s:
    li[ord(i)-97]+=1
maxi=-1
for i in range(26):
    if li[i]==0:
        continue
    maxi=max(maxi,l[i])
print maxi*len(s)