from itertools import accumulate
N = int(input())
S = str(input())
A = list(map(int,input().split()))
for i in range(N):
    if S[i] == 'B':
        A[i] = -A[i]
AC = [0]+list(accumulate(A))

mi,ma = 10**18,-10**17
for i in range(N):
    mi = min(mi,min(AC[i+1:])-AC[i])
    ma = max(ma,max(AC[i+1:])-AC[i])
ans = max(abs(mi),ma)
print(ans)