#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);
    stack.push(make_pair(s[first++], 0));
    while(first < N){
        if(s[first] == '('){
            // cout << "stacked " << first << endl;
            stack.push(make_pair(s[first], first));
        } else if(s[first] == ')'){
            // cout << "poped " << first << endl;
            auto index = stack.top();
            stack.pop();
            pindex[first] = index.second;
            pindex[index.second] = first;
        }
        first++;
    }
    // for(int i=0;i<N;++i){
    //     cout << pindex[i]+1 << endl;
    // }
    cout << pindex[K-1]+1 << endl;
    return 0;
}