n = int(input())
s = input()
a = list(map(int, input().split()))
b = [0] * (n + 1)
for i in range(n):
    if s[i] == 'R':
        b[i + 1] = b[i] + a[i]
    else:
        b[i + 1] = b[i] - a[i]
ans = 0
m = 0
for i in range(n):
    m = min(m, b[i + 1])
    ans = max(ans, b[i + 1] - m)
m = 0
for i in range(n):
    m = max(m, b[i + 1])
    ans = max(ans, m - b[i + 1])
print(ans)