n = int(input())
s = input()
a = list(map(int,input().split()))
dp = [0]+[10**12]*n
for i,(t,v) in enumerate(zip(s,a)):
    eq = [10**12]*(n+1)
    for i in range(n): eq[i+1] = min(eq[i+1],dp[i]+v*(t==")"))
    for i in range(n): eq[i] = min(eq[i],dp[i+1]+v*(t=="("))
    dp = eq
print(dp[0])