#include <bits/stdc++.h> 

using namespace std;

int main() {
    int N, K; cin >> N >> K;
    string S; cin >> S;
    vector<int> dp(N);
    stack<int> P;
    for (int i = 0; i < N; i++) {
        if (S[i] == '(') {
            P.push(i);
        } else {
            int num = P.top(); P.pop();
            dp[i] = num;
            dp[num] = i;
        }
    }
    // for (auto v : dp) { cout << v << " "; }
    // cout << endl;
    cout << dp[K - 1] + 1 << endl;
}