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