n = int(input())
S = input()
A = list(map(int,input().split()))
ans = 0
mi = 0
ma = 0
count = 0
for s,a in zip(S,A):
    if s == "R":
        count += a
    else:
        count -= a
    ans = max(ans,abs(count-mi))
    ans = max(ans,abs(count-ma))
    mi = min(mi,count)
    ma = max(ma,count)
print(ans)