n=int(input())
s=list(input())
v=list(map(int,input().split()))
taken=[0]*n
pre=-1
ans=0
while pre!=ans:
  y=[0,-1]
  yu=[0,-1,-1]
  yuk=[0,-1,-1,-1]
  yuki=[0,-1,-1,-1,-1]
  pre=ans
  for i in range(n):
    if taken[i]==1:continue
    if s[i]=='y':
      if y[0]<v[i]:
        y=[v[i],i]
    elif s[i]=='u' and y[0]>0:
      if yu[0]<v[i]+y[0]:
        yu=[v[i]+y[0],y[1],i]
    elif s[i]=='k' and yu[0]>0:
      if yuk[0]<v[i]+yu[0]:
        yuk=[v[i]+yu[0],yu[1],yu[2],i]
    elif s[i]=='i' and yuk[0]>0:
      if yuki[0]<v[i]+yuk[0]:
        yuki=[v[i]+yuk[0],yuk[1],yuk[2],yuk[3],i]
  if yuki[0]>0:
    ans+=yuki[0]
    taken[yuki[1]]=1
    taken[yuki[2]]=1
    taken[yuki[3]]=1
    taken[yuki[4]]=1
print(ans)