N = int(input())
S = input().strip()
A = list(map(int,input().split()))
for i in range(N):
    if S[i]=="R":
        A[i] = -A[i]
A = [0]+A
B = [0]*(N+1)
for i in range(1,N+1):
    B[i] = B[i-1]+A[i]
bmax = max(B)
bmin = min(B)
print(bmax-bmin)