#include<vector>
#include<map>
#include<climits>
#include<set>
#include<queue>
#include<stack>
#include<algorithm>
#include<functional>
#include<numeric>
#include<utility>
#include<sstream>
#include<iostream>
#include<iomanip>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cctype>
#include<string>
#include<bitset>
#include<cstring>
#include<list>
#include<iterator>
using namespace std;
typedef vector<string>vs;
typedef vector<int>vi;
typedef vector<vi>vvi;
typedef pair<int,int>pii;
typedef long long ll;
typedef pair<ll,ll>pll;
#define rrep(i,x,n) for(int i=(x);i<(n);++i)
#define rep(i,x) rrep(i,0,(x))
#define fi first
#define se second
#define each(i,c) for(typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define all(c) (c).begin(),(c).end()
#define rall(c) (c).rbegin(),(c).rend()
#define pb push_back
#define maxs(a,b) (a)=max(a,b)
#define mins(a,b) (a)=min(a,b)



int main(){
    int N,K;cin>>N>>K;
    string str;cin>>str;

    stack<int>S;

    rep(i,N){
        if(str[i]=='(')S.push(i+1);
        else{
            int val=S.top();S.pop();
            if(val==K)cout<<i+1<<endl;
            else if(i+1==K)cout<<val<<endl;
            else continue;
            break;
        }
    }

    return 0;
}