#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;

#define rep(i, r) for(int i = 0; i < (r); ++i)
#define reps(i, s, r) for(int i = (s); i < (r); ++i)
#define rrep(i, a, b) for(int i = a; i >= b; i--)
#define fore(i, m2) for(auto &i : m2)
#define vi vector<int>
#define vl vector<ll>
#define pl pair<ll, ll>
#define all(i) (i).begin(), (i).end()
#define fs first
#define sc second

template <class T> bool chmin(T &i, T b) {
    if(i > b) {
        i = b;
        return true;
    }
    return false;
}
template <class T> bool chmax(T &a, T b) {
    if(a < b) {
        a = b;
        return true;
    }
    return false;
}

const ll INF = LONG_LONG_MAX / 3;
const ll MOD = 1'000'000'007;
const ll MAX = 1e5 + 5;

#define EPS 0.000000001
using namespace std;

int main() {

    ll n, k;
    string s;
    cin >> n >> k;
    cin >> s;

    stack<ll> stk;
    ll a[n];

    rep(i, n) {
        if(s[i] == '(') {
            stk.push(i);

        } else {
            ll v = stk.top();
            a[v] = i;
            a[i] = v;
            stk.pop();
        }
    }

    cout << a[k - 1] + 1 << endl;
}