#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<string>

using namespace std;

int main(){
	int n,k,count=1;
	string s;
	cin >> n >> k >> s;

    vector<int> v(n);
    vector<int> vlen(n);
    for(int i=0; i< s.length(); i++){
        v[i] = (s[i] == '(')? 1: 2;
    }
    
    for(int i=0; i<n; i++){
        if(v[i] == 0) continue; 
        for(int j=i+1; j<n; j++){
            if(v[i] == 1 && v[j] == 1) break;
            if(v[i] == 1 && v[j] == 2){
                v[i] = 0;
                v[j] = 0;
                vlen[i] = count;
                vlen[j] = count;
                count++;
                i=-1;
                break;
            }
        }
    }


    int tmp = vlen[k-1];
    for(int i=0; i<n; i++){
        if(tmp == vlen[i] && i != k-1){
            cout << i+1 << endl;
            break;
        }
    }
}