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

cumsum = [0]
for i, s in enumerate(list(S)):
    if s == "B":
        A[i] = -A[i]
    cumsum.append(cumsum[-1] + A[i])

x = -float('inf')
for i in range(0, len(cumsum)-1):
    for k in range(i+1, len(cumsum)):
        a = abs(cumsum[k] - cumsum[i])
        x = max(a, x)

print(x)