n = int(input())
S = input()
A = list(map(int, input().split()))
inf = 1 << 60
dp = [inf] * (n + 1)
dp[0] = 0
for s, a in zip(S, A):
    if s == "(":
        u = 0
        d = a
    else:
        u = a
        d = 0

    ndp = [inf] * (n + 1)
    for i in range(n):
        ndp[i] = min(ndp[i], dp[i + 1] + d)
        ndp[i + 1] = min(ndp[i + 1], dp[i] + u)
    dp = ndp

print(dp[0])