N=int(input())
S=input()
A=list(map(int,input().split()))
for i in range(N):
  if S[i]=='B':
    A[i]*=-1
DP=[[0,0] for i in range(N+1)]
for i in range(N):
  DP[i+1][0]=min(DP[i][0]+A[i],A[i])
  DP[i+1][1]=max(DP[i][1]+A[i],A[i])
print(max([max(-DP[i][0],DP[i][1]) for i in range(N+1)]))