N = int(input())
S = input()
lsa = list(map(int,input().split()))
lsB = []
lsR = []

ll = []
for i in range(N):
    if S[i] == 'R':
        ll.append(lsa[i])
    else:
        ll.append(-lsa[i])

lssum = [0]
for i in range(N):
    lssum.append(lssum[-1]+ll[i])
print(max(lssum)-min(lssum))