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

tot = 0
max_ = 0
min_ = 0
ans = 0
for a in A:
    tot += a
    min_ = min(min_, tot)
    max_ = max(max_, tot)
    ans = max(ans, max_ - tot, tot - min_)
print(ans)