#int(input())
#map(int, input().split())
#list(map(int, input().split()))

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

s = [0] * (N+1)
for i in range(N):
    if S[i] == "R":
        s[i+1] = s[i] + a[i]
    else:
        s[i+1] = s[i] - a[i]

print(max(s)-min(s))