#include <iostream>
#include <stack>

using namespace std;

int main(){
    int numberOfTests = 6;

//    for (int j = 0; j < numberOfTests; ++j) {
        int n, result = 0;
        char current, prev;

        cin >> n;

//        for (int i = 0; i < n; ++i) {
//            cin >> current;
//            if(i != 0) { //first
//                if(current == '(' && prev == ')') { // +
//
//                } else if (current == ')' && prev == '(') { // 1
//                    result += 1;
//                } else if (current == ')' && prev == ')') { // + 1
//                    result += 1;
//                }
//            }
//            prev = current;
//        }

        stack<char> s;
        bool first = true;
        char next;
        char t;
        for (int i = 0; i < n; ++i) {
            cin >> t;
            s.push(t);
        }

        while (!s.empty()) {
            current = s.top();
            s.pop();
            if (first) {
                first = false;
            } else {
                if(next == '(' && current == ')') { // +

                } else if (next == ')' && current == '(' ) {
                    result+=1;
                } else if (next == ')' && current == ')') {
                    result+=1;
                }
            }
            next = current;
        }

        cout << result << endl;
//    }


    return 0;
}