#include <iostream>
#include <utility>
#include <vector>
using namespace std;

typedef pair<char, int> PCI;

int main(void){
  int n,k;
  vector<PCI> stk;
  char c;
  
  cin >> n >> k;
  for (int i=1; i<=n; i++){
    cin >> c;
    if (c=='(') stk.push_back(make_pair(c,i));
    else { // c==')'
      PCI pci = stk.back();
      if (i==k) cout << pci.second << endl;
      if (pci.second==k) cout << i << endl;
      stk.pop_back();
    }
  }
  return 0;
}