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

int main() {
    int n,k;
    std::cin >> n >> k;
    std::string s;
    std::cin >> s;
    
    std::stack<int> st;
    std::vector<int> ans(n);

    for (int i = 0; i < n; i++) {
        if (s[i] == '(') {
            st.push(i);
        } else {
            int a = st.top();
            st.pop();
            
            ans[i] = a;
            ans[a] = i;
        }
    }

    std::cout << ans[k-1] + 1 << std::endl;
    
    return 0;
}