#include<iostream>
#include<stack>
#include<string>

using namespace std;

int main(){

	stack<int> data;
	int N,K;
	string s;

	cin>>N>>K;
	cin>>s;

	for(int i=0;i<N;i++){
		if(s[i]=='(') data.push(i+1);
		if(s[i]==')'){
			if(data.empty()){
				cout<<"error data"<<endl;
				return 0;
			}
			if(data.top()==K||i+1==K){
				cout<<((i+1==K)?data.top():i+1)<<endl;
				return 0;
			}
			data.pop();
		}
	}

	cout<<"NO MATCH"<<endl;
}