#include<bits/stdc++.h>

#define INF 1000000007
#define LINF 1000000000000000007

using namespace std;

typedef long long Int;
typedef pair<Int, Int> P;

int n;
P r[100000];
string s;

int main(){
	cin >> n;
	cin >> s;
	
	if(s[0] == ')') r[0] = make_pair(1, 0);
	else r[0] = make_pair(0,0);
	bool y = 0, x = 0;
	if(s[0] == ')') y = 1;
	else x = 1;
	for(int i = 1; i < n; i++){
		r[i].first = r[i-1].first;
		if(s[i] == ')'){r[i].first++; y = 1;}
		else x = 1;
		r[i].second = i;
	}
	
	if(!x || !y){cout << 0 << endl; return 0;}
	sort(r, r+ n);
	Int cnt = 0, migi = 0, hidari = 0;
	for(int i = 1; i < n; i++){
		int j = i, k = i;
		while(r[j-1].first == r[j].first){
			j++;
		}
		i = j;
		while(j >= k){
			if(j != 0) migi += r[j].first;
			hidari += r[j-1].second - r[j-1].first + 1;
			cnt += min(migi, hidari)*2;
			migi -= min(migi, hidari);
			hidari -= min(migi, hidari);
			j--;
		}
	}
	
	cout << cnt << endl;
	
	return 0;
}