#include<bits/stdc++.h>
using namespace std;
#define NUM 10000
int num[NUM];
int main(){
    int N, K; cin >> N >> K;
    string S; cin >> S;
    stack<int> head;
    for(int i=0; i<N; i++){
        if(S[i] == '('){
            head.push(i);
        }
        if(S[i] == ')'){
            int j = head.top();head.pop();
            num[i] = j+1;
            num[j] = i+1;
        }
    }
    cout << num[K-1] << endl;

    return 0;
}