#include <iostream>
#include <string>
#include <vector>
#include <sstream>
using namespace std;

#define ll long long
#define vec vector<ll>

ll min(ll a, ll b){
    return (a < b ? a : b);
}

ll max(ll a, ll b){
    return (a > b ? a : b);
}

int main(){
    ll len, sum = 0;
    cin >> len;
    char c, last_char;
    cin >> last_char;
    if(last_char == '('){
        sum++;
    }
    while(len--){
        cin >> c;
        // if(c == '(')
        //     sum++;
        if(c == ')' && last_char == ')')
            sum++;
        last_char = c;
    }
    cout << sum << endl;
    return 0;
}