n=int(input())
s=input()
a=list(map(int,input().split()))
maxi=0
mini=0
curr=0
for i in range(n):
  if s[i]=='R':
    curr+=a[i]
  else:
    curr-=a[i]
  maxi=max(maxi,curr)
  mini=min(mini,curr)
print(maxi-mini)