N=int(input())
S=input().rstrip()
A=list(map(int, input().split()))
B=[]
for i in range(N):
    if S[i]=="R":
        B.append(A[i])
    else:
        B.append(-A[i])

S=[0]
for b in B:
    S.append(S[-1]+b)

m,M=0,0


res=0

for s in S:
    if s>=0:
        res=max(s-m,res)
    else:
        res=max(M-s,res)
    m=min(s,m)
    M=max(s,M)

print(res)