#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

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

    vector<int> v(n);
    stack<int> stk;
    for(int i=0; i<n; ++i){
        if(s[i] == '('){
            stk.push(i);
        }
        else{
            int j = stk.top();
            stk.pop();
            v[i] = j;
            v[j] = i;
        }
    }
    cout << (v[k-1] + 1) << endl;

    return 0;
}