#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < n; i++) //[0,n)
#define srep(i,a,b) for(int i = a; i < b; i++) //[a,b)
#define all(A) (A).begin(),(A).end()
#define rall(A) (A).rbegin(),(A).rend()
#define pmt(A) next_permutation(A)
using namespace std;
using ll = long long;
using ull = unsigned long long;
using P = pair<ll,ll>;
using pq = priority_queue<ll,vector<ll>,greater<ll>>;
//smaller
const ll inf = 8e18;
const int iinf = (int)1e9;
const int mod9 = 998244353;
const int mod1 = 1000000007;
struct Edge {
    int to;
    ll cost;
    //int from;
};
bool compe(const Edge &e,const Edge &e2){ return e.cost < e2.cost; }
using Graph = vector<vector<int>>;
using EGraph = vector<Edge>;
using SGraph = vector<set<ll>>;
template <typename T>
int siz(T& a){ return (int)a.size(); }
double squa(double x){ return 1.0*x*x; }
double pi = acos(-1);
double chrad(int d){ return 1.0*d/180*pi; }
using namespace std;

int main(){
    int n,k; cin >> n >> k;
    string s; cin >> s;

    stack<int> Q;
    vector<P> ans;
    rep(i,n){
        if(s[i] == '(') Q.push(i);
        else {
            ans.push_back({i,Q.top()});
            Q.pop();
        }
    }
    
    for(auto& [p,p2] : ans){
        if(p+1 == k){
            cout << p2+1;
            break;
        } else if(p2+1 == k){
            cout << p+1;
            break;
        }
    }
}