#include <bits/stdc++.h>
using namespace std;

int main(){
    int N, K;
    cin >> N >> K;
    string s;
    cin >> s;

    int first = 0;
    stack<pair<char, int>> stack;
    vector<int> pindex(N);
    pindex[0] = 1;
    stack.push(make_pair(s[first++], 1));
    while(!stack.empty()){
        if(s[first] == '('){
            stack.push(make_pair(s[first], first+1));
        } else if(s[first] == ')'){
            auto index = stack.top();
            stack.pop();
            pindex[first] = index.second;
            pindex[index.second] = first;
        }
        first++;
    }
    cout << pindex[K-1] << endl;
    return 0;
}