N = int(input())
S = list(input())
A = list(map(int, input().split()))
for i in range(N):
    if S[i] == "R":
        A[i] = -A[i]
        
ma, mi = 0, 0
ans = 0
for i in range(N):
    ma = max(0, ma + A[i])
    mi = min(0, mi + A[i])
    ans = max(ans, ma, -mi)
print(ans)