#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <stack>

using namespace std;

struct Coord {
    int x, y;
};

int main() {
    int n, k;
    std::cin >> n >> k;
    std::vector<int> b(n);
    std::stack<int> s;
    for (int i = 0; i < n; i++) {
        char c;
        std::cin >> c;
        if (c == '(') {
            s.push(i);            
        } else {
            b[i] = s.top();
            b[s.top()] = i;
            s.pop();
        }
    }
    
    std::cout << b[k - 1] + 1 << std::endl;

    return 0;
}