N = int(input())
S = input()
A = tuple(map(int, input().split()))

dp = [0] * (N + 1)
for i in range(N):
    a = -A[i] if S[i] == "R" else A[i]
    dp[i+1] = dp[i] + a

ans = 0
vmin = 10 ** 18
vmax = -10 ** 18
for v in dp:
    vmin = min(vmin, v)
    vmax = max(vmax, v)
    ans = max(ans, abs(vmin-vmax))
print(ans)