#include <iostream>
#include <algorithm>

using namespace std;

char c[200000];
int b[200000];

int main()
{
	int n, mn = 1e9, ans = 0;
	char t;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> c[i];
		if (c[i] == '(') b[i] = b[max(0, i - 1)] + 1;
		else b[i] = b[max(0, i - 1)] - 1;
		mn = min(mn, b[i]);
	}
	if (mn < -1 || b[n - 1] > 1  || !b[n - 1] || (b[n - 1] ==1 && mn < 0)) return cout << 0, 0;
	if (b[n - 1] == 1) t = ')';
	else t = '(';
	if (t == '(')
	{
		for (int i = 0; i < n; i++)
		{
			if (c[i] != t) ans++;
			if (b[i] == -1) break;
		}
	}
	else
	{
		for (int i = n - 1; i > -1; i--)
		{
			if (!b[i]) break;
			if (c[i] != t) ans++;

		}
	}
	cout << ans;
    return 0;
}