#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <utility>
#include <stack>
#include <functional>
#include <queue>
#include <cmath>
#include <set>

#define rep(i,j,k) for(int i=j;i<k;i++)
#define Sort(x) sort((x).begin(),(x).end())
#define fi first
#define se second
#define vi vector<int>
#define INF 1000000000
#define MOD 1000000009
#define pb push_back
#define mp make_pair
typedef long long ll;
typedef std::pair<int,int> pii;
int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};

using namespace std;


int main() {
    int n,m;
    cin>>n>>m;
    string s;
    cin>>s;
    stack<int> st;
    rep(i,0,n){
        if(i==0)st.push(i+1);
        else {
            if(s[i]=='(')st.push(i+1);
            else {
                if(st.top()==m){
                    cout<<i+1<<endl;
                    return 0;
                }else if(i+1==m
                ){
                    cout<<st.top()<<endl;
                    return 0;
                }
                st.pop();
                
            }
        }
    }

    
    return 0;
}