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

int main(){

    int N,K;
    string S;
    cin >> N >> K >> S;

    vector<int> p(N+1);
    stack<int> sta;

    for(int i=0; i<S.size(); i++){
        if(S[i]=='(')sta.push(i+1);
        else{
            p[i+1] = sta.top();
            p[sta.top()] = i+1;
            sta.pop();
        }
    }
    
    cout << p[K] << endl;
    
    return 0;
}