#include <bits/stdc++.h>
#define PB push_back
#define MP make_pair
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define ALL(a) (a).begin(),(a).end()
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
const int INF=1e9;
int main(){
      int n,k;
      string s;
      cin>>n>>k>>s;k--;
      stack<int> Q;
      REP(i,s.size()){
            if(s[i]=='('){
                  Q.push(i);
            }else{
                  int t=Q.top();Q.pop();
                  if(s[k]=='('&&t==k)cout<<i+1<<endl;
                  else if(s[k]==')'&&k==i)cout<<t+1<<endl;
            }
      }
}