from atcoder.segtree import SegTree

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

INF = 10 ** 15
ST1 = SegTree(max, -INF, B)
ST2 = SegTree(min, INF, B)
ans = 0
for i in range(N + 1):
    ans = max(ans, abs(ST1.prod(i, N + 1) - B[i]))
    ans = max(ans, abs(ST2.prod(i, N + 1) - B[i]))
print(ans)