#include "bits/stdc++.h"
using namespace std;

typedef long long Int;
#define REP(i,n) for(int (i)=0;(i)<(int)(n);++(i))

int pi[10000];
int st[10000];

int main() {
	int N, K;
	cin >> N >> K;
	K--;
	string s; cin >> s;
	
	
	int sp = 0;
	REP(i, N) {
		if (s[i] == '(') { st[sp++] = i; }
		else {
			int j = st[--sp];
			pi[i] = j;
			pi[j] = i;
		}
	}
	cout << pi[K] + 1 << endl;

}