#include <vector> 
#include <list> 
 #include <map>
 #include <set>
#include <deque>
#include <stack>
#include <bitset>
#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 <cstring>
#include <ctime>
#include <queue>
using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

//debug
#define dump(x)  cerr << #x << '=' << (x) << endl;
#define debug(x) cerr << #x << '=' << (x) << '('<<'L' << __LINE__ << ')' << ' ' << __FILE__ << endl;

int N;
int K;
string s;
int main(){
    
    cin>>N>>K;
    cin>>s;
    VI PairIndex(N);
    fill(PairIndex.begin(),PairIndex.end(),100001);
    // REP(i,s.size()){
    //     if(s[i]=='('){ 
    //         FOR(j,i+1,s.size()){
    //             if(s[j]==')'&&PairIndex[j]==100001){
    //                 PairIndex[i]=j;
    //                 PairIndex[j]=i;
    //                 goto NEXT;
    //             }
    //         }
    //     }
    //     NEXT:;
    // }

    // REP(i,s.size()){
    //     cout<<PairIndex[i]<<" ";
    // }
    // cout<<endl;
    stack<int> rightpos;
    REP(i,s.size()){
        if(s[i]=='('){rightpos.push(i);}
        if(s[i]==')'){ int a=rightpos.top(); rightpos.pop(); PairIndex[i]=a; PairIndex[a]=i;   }
    }

    // REP(i,s.size()){
    //     cerr<<PairIndex[i]<<" ";
    // }
    // cerr<<endl;

    cout<<PairIndex[K-1]+1<<endl;
}