using namespace std;
#include <bits/stdc++.h>
#define BEGIN ios_base::sync_with_stdio(0);cin.tie(0);
#define END return EXIT_SUCCESS;
#define FOR(I,A,B) for(int (I)=(A);(I)<(B);++(I))
#define ALL(C) (C).begin(),(C).end()
inline void solve()
{
	int N,K;
	string S;
	int t;
	int I[10001];
	cin>>N>>K>>S;
	stack<int> T;
	FOR(i,0,N)
	{
		if(S[i]=='(')
		{
			T.push(i);
		}
		else
		{
			t = T.top();
			T.pop();
			I[t] = i;
			I[i] = t;
		}
	}
	cout<<(I[K-1]+1)<<endl;
}
int main(int argc,char**argv)
{
	BEGIN
	solve();
	END
}