#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000005
#define Inf64 4000000000000000001LL
struct Data{
	int sum,pm;
};
Data op(Data a,Data b){
	Data c;
	c.sum = a.sum + b.sum;
	c.pm = min(a.pm,a.sum + b.pm);
	return c;
}
Data e(){
	Data c;
	c.pm = 0;
	c.sum = 0;
	return c;
}
int main(){
	
	int n;
	cin>>n;
	string s;
	cin>>s;
	if(n%2==1){
		cout<<-1<<endl;
		return 0;
	}
	segtree<Data,op,e> seg(n*2);
	rep(i,n*2){
		if(s[i%n]=='('){
			seg.set(i,Data{1,0});
		}
		else{
			seg.set(i,Data{-1,-1});
		}
	}
	long long R,M;
	cin>>R>>M;
	long long ans = Inf64;
	rep(i,n){
		Data res = seg.prod(i,i+n);

		long long c = (n-i)%n;
		c *= R;
		c += ((1+(-res.pm))/2)*M;
		res.sum += ((1+(-res.pm))/2)*2;
		c += (res.sum/2) * M;
		ans = min(ans,c);
	}
	cout<<ans<<endl;
	return 0;
}