n = int(input())
s = input()
a = list(map(int, input().split()))
x = [0]
for i in range(n):
  if s[i] == "R":
    x.append(x[-1]+a[i])
  else:
    x.append(x[-1]-a[i])
ans=0
mi=0
for i in range(1, n+1):
  ans = max(ans, x[i]-mi)
  mi = min(x[i], mi)
print(ans)